Control device, motor device, electric power steering device, control method, and program

Abstract

In electric power steering systems, this suppresses a decrease in responsiveness during lane keeping control. [Solution] The control device is capable of performing lane keeping control and comprises a first assist control unit that generates a first input value, a second assist control unit that generates a second input value based on a steering input value, and a disturbance sensitivity control unit that receives a command value calculated based on the first and second input values. The disturbance sensitivity control unit has a model following control unit that generates a correction value to correct the command value. The first assist control unit has a generation unit that generates a first input value based on a target value of the output of the deceleration mechanism, and a second output value indicating the output of the deceleration mechanism is fed back. The generation unit has a compensation unit that performs phase delay compensation processing for the phase delay that occurs in the second output value that is fed back.

Description

[Technical Field]

[0001] The present invention relates to a control device, a motor device, an electric power steering device, a control method, and a program. [Background technology]

[0002] An electric power steering system installed in a vehicle is known (for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-183046 [Overview of the project] [Problems that the invention aims to solve]

[0004] The electric power steering systems described above may include, for example, a control device capable of performing lane keeping control. Lane keeping control is a control system that uses a motor to provide driving force to the steering mechanism when the vehicle is about to deviate from its lane, thereby keeping the vehicle within the lane. In performing such lane keeping control, there is a technique that enables lane keeping control with simple control by constraining the controlled object to a simple model using model following control. In such model following control, disturbance estimation and compensation are performed, for example, based on the steering angle. However, if the feedback signal of the steering angle is delayed due to, for example, the length of the communication cycle, the frequency band in which disturbances can be estimated and compensated for by model following control may be limited, and the responsiveness of lane keeping control may decrease.

[0005] In view of the above circumstances, one of the objectives of the present invention is to provide a control device, a motor device, an electric power steering device, a control method, and a program that can suppress a decrease in responsiveness in lane keeping control. [Means for solving the problem]

[0006] One aspect of the control device of the present invention is a control device for controlling a portion of an electric power steering system mounted on a vehicle, which has an input shaft to which a steering wheel operated by an helmsman is connected, an output shaft connected to the input shaft via a torsion bar, and a motor connected to the output shaft via a reduction mechanism, the control device being capable of performing lane keeping control to keep the vehicle within a lane, and comprising: a first assist control unit that generates a first input value; a second assist control unit that generates a second input value based on a steering input value input from the steering wheel; and a disturbance sensitivity control unit to which a command value calculated based on the first input value and the second input value is input. The disturbance sensitivity control unit has a model following control unit that generates a correction value to correct the command value based on a nominal model based on the configuration of the control device. The model-following control unit has an inverse nominal model which is the inverse model of the nominal model and receives a third input value based on a first output value indicating the output of the motor, and is configured such that the transfer function of the controlled object is constrained to the transfer function of the nominal model in a frequency band where the complementary sensitivity gain, which is the gain in the gain characteristic of the complementary sensitivity function for the modeling error between the controlled object and the nominal model, is approximately 1. The first assist control unit has a generation unit which generates the first input value based on a target value of the output of the reduction mechanism. A second output value indicating the output of the reduction mechanism is fed back to the generation unit. The generation unit has a compensation unit which performs phase delay compensation processing for the phase delay that occurs in the second output value that is fed back.

[0007] One embodiment of the motor device of the present invention comprises the control device described above and the motor.

[0008] One embodiment of the electric power steering device of the present invention comprises the above-described motor device and a steering mechanism having the input shaft, the output shaft, and the torsion bar.

[0009] One aspect of the control method of the present invention is a control method for controlling a portion of an electric power steering device mounted on a vehicle, which has an input shaft to which a steering wheel operated by an operator is connected, an output shaft connected to the input shaft via a torsion bar, and a motor connected to the output shaft via a reduction mechanism, the portion including the motor and the reduction mechanism being controlled, the method comprising: generating a first input value and performing lane keeping control to maintain the vehicle within the lane; generating a second input value based on a steering input value input from the steering wheel; performing model following control to generate a correction value for correcting a command value calculated based on the first input value and the second input value, based on a nominal model based on the configuration of the controlled object; and, by the model following control, constraining the transfer function of the controlled object to the transfer function of the nominal model in a frequency band where the complementary sensitivity gain, which is the gain in the gain characteristics of the complementary sensitivity function for the modeling error between the controlled object and the nominal model, is approximately 1. In the model-following control described above, a third input value based on a first output value indicating the output of the motor is input to an inverse nominal model, which is the inverse model of the nominal model. The lane-keeping control includes generating the first input value based on a target value of the output of the deceleration mechanism, receiving a second output value indicating the output of the deceleration mechanism as feedback, and performing phase delay compensation processing for the phase delay that occurs in the second output value that is fed back.

[0010] One aspect of the program of the present invention involves causing a computer to execute the above-described control method. [Effects of the Invention]

[0011] According to one aspect of the present invention, it is possible to suppress a decrease in responsiveness in lane keeping control in an electric power steering system. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram showing an electric power steering system in the first embodiment. [Figure 2] Figure 2 is a block diagram showing the configuration of the control device in the first embodiment. [Figure 3] Figure 3 is a schematic diagram showing a vehicle equipped with the lane keeping system in the first embodiment traveling in a lane. [Figure 4] Figure 4 is a block diagram showing the configuration of the lane keeping system in the first embodiment. [Figure 5] Figure 5 is a block diagram showing the configuration of the imaging device and the first assist control unit in the first embodiment. [Figure 6] Figure 6 is a diagram illustrating lane keeping control in the first embodiment. [Figure 7] Figure 7 is a block diagram showing the configuration of the second assist control unit in the first embodiment. [Figure 8] Figure 8 is a graph showing an example of the relationship between input torque and assist torque in the first embodiment. [Figure 9] Figure 9 is a block diagram showing the configuration of the vehicle stabilization control unit in the first embodiment. [Figure 10] Figure 10 is a Bode plot showing the gain of the transfer function of the second nominal model in the first embodiment. [Figure 11] Figure 11 is a block diagram showing the configuration of the second state feedback unit in the first embodiment. [Figure 12] Figure 12 is a block diagram showing the configuration of the disturbance sensitivity control unit in the first embodiment. [Figure 13] Figure 13 is a graph illustrating the gain characteristics of the complementary sensitivity function of the first model-following control unit in the first embodiment, and the gain characteristics of the reciprocal of the modeling error between the transfer function of the first controlled object and the transfer function of the first nominal model. [Figure 14] Figure 14 is a graph showing an example of the relationship between steering angle and self-aligning torque. [Figure 15] Figure 15 is a block diagram showing the configuration of the arithmetic unit in the first embodiment. [Figure 16] Figure 16 is a graph showing an example of the gain of the high-frequency output value and the gain of the low-frequency output value in the first embodiment. [Figure 17] Figure 17 is a block diagram showing the configuration of the lane keeping system in the second embodiment. [Figure 18] Figure 18 is a block diagram showing the configuration of the generation unit in the third embodiment. [Modes for carrying out the invention]

[0013] <First Embodiment> The electric power steering system 1000 of this embodiment, shown in Figure 1, is mounted on a vehicle V. As shown in Figure 1, the electric power steering system 1000 comprises a steering mechanism 530 and a control device 100. The steering mechanism 530 has a steering mechanism section 520 and an auxiliary mechanism section 540. The electric power steering system 1000 controls the auxiliary mechanism section 540 by the control device 100, thereby generating a steering torque T in the steering mechanism section 520 when the driver operating the vehicle V steers the steering wheel 521. h It generates an auxiliary torque to assist the steering. This auxiliary torque reduces the burden on the driver when operating the steering wheel 521. The driver of vehicle V is the helmsman who steers the steering wheel 521 of vehicle V.

[0014] The steering mechanism 520 includes a steering wheel 521, a steering shaft 522, universal joints 523A, 523B, an input shaft 524a, an output shaft 524b, a rack and pinion mechanism 525, a rack shaft 526, left and right ball joints 552A, 552B, tie rods 527A, 527B, knuckles 528A, 528B, and left and right tires 529A, 529B. In other words, the steering mechanism 530 includes a steering wheel 521, a steering shaft 522, universal joints 523A, 523B, an input shaft 524a, an output shaft 524b, a rack and pinion mechanism 525, a rack shaft 526, left and right ball joints 552A, 552B, tie rods 527A, 527B, knuckles 528A, 528B, and left and right tires 529A, 529B.

[0015] The steering shaft 522 is a shaft that extends from the steering wheel 521, which is operated by the driver. One end of the input shaft 524a is connected to the end of the steering shaft 522 opposite to the side connected to the steering wheel 521, via universal joints 523A and 523B. Thus, the steering wheel 521 is connected to the input shaft 524a via the universal joints 523A and 523B and the steering shaft 522. The output shaft 524b is connected to the input shaft 524a via a torsion bar 546, which will be described later. More specifically, one end of the output shaft 524b is connected to the other end of the input shaft 524a via the torsion bar 546. The other end of the output shaft 524b is connected to the rack shaft 526 via a rack and pinion mechanism 525.

[0016] The input shaft 524a and the output shaft 524b are arranged coaxially. The input shaft 524a and the output shaft 524b are rotatable around the same central axis. The input shaft 524a and the output shaft 524b are rotatable relative to each other within the range in which the torsion bar 546, described later, can twist.

[0017] The auxiliary mechanism unit 540 includes a steering torque sensor 541, a motor 543, a reduction mechanism 544, an inverter 545, and a torsion bar 546. That is, the steering mechanism 530 includes a steering torque sensor 541, a motor 543, a reduction mechanism 544, an inverter 545, and a torsion bar 546. The torsion bar 546 connects the input shaft 524a and the output shaft 524b. The torsion bar 546 is arranged coaxially with the input shaft 524a and the output shaft 524b. In the following description, a virtual axis passing through the common central axis of the input shaft 524a, the output shaft 524b, and the torsion bar 546 is referred to as the rotation axis R. The torsion bar 546 can be twisted around the rotation axis R.

[0018] The steering torque sensor 541 detects the steering torque T in the steering mechanism unit 520 by detecting the amount of twist around the rotation axis R of the torsion bar 546 h and detects it. The steering torque T h is the torsion bar torque generated in the torsion bar 546 and is the torsional moment around the rotation axis R.

[0019] The rotation angle around the rotation axis R of the steering shaft 522 is detected by the steering angle sensor 542. The rotation angle around the rotation axis R of the steering shaft 522 is the steering angle θ h of the steering wheel 521 and is equal to the rotation angle θ a of the input shaft 524a. That is, the steering angle sensor 542 can detect the rotation angle of the steering shaft 522 and thereby detect the rotation angle θ a of the input shaft 524a and the steering angle θ h of the steering wheel 521. Based on the steering torque sensor 541 and the steering angle sensor 542, it is possible to detect the rotation angle θ b of the output shaft 524b. The rotation angle θ b of the output shaft 524b is the steering angle θ s . The detection result of the steering angle sensor 542 is transmitted to the control device 100 using, for example, CAN (Controller Area Network).

[0020] The inverter 545 converts DC power, which is a pseudo-sine wave of U-phase, V-phase, and W-phase, into three-phase AC power according to the motor drive signal input from the control device 100 and supplies it to the motor 543. The motor 543 is connected to the output shaft 524b via the reduction mechanism 544. The motor 543 is supplied with three-phase AC power from the inverter 545. The motor 543 is, for example, an Interior Permanent Magnet Synchronous Motor (IPMSM), a Surface Mounted Permanent Magnet Synchronous Motor (SPMSM), or a Switched Reluctance Motor (SRM). The motor 543, supplied with three-phase AC power from the inverter 545, provides steering torque T h It generates an auxiliary torque corresponding to the current. The motor 543 transmits the generated auxiliary torque to the output shaft 524b via the reduction mechanism 544.

[0021] The control device 100 is a control device that controls the steering mechanism 530 mounted on the vehicle V. In this embodiment, the control device 100 can control the first controlled object 560. The first controlled object 560 is a controlled object that includes a motor 543 provided on the steering mechanism 530. In this embodiment, the first controlled object 560 has a steering mechanism 520, a torsion bar 546, a motor 543, and a reduction mechanism 544. Since the first controlled object 560 includes an input shaft 524a and an output shaft 524b that can rotate relative to each other via the torsion bar 546, the motion of the first controlled object 560 cannot be described by the equation of motion of a simple one-inertial frame only. The first controlled object 560 changes between one-inertial frame and two-inertial frame depending on how hard the helmsman grips the steering wheel 521. The harder the helmsman grips the steering wheel 521, the closer the first controlled object 560 gets to one-inertial frame. The more lightly the helmsman grips the steering wheel 521, the closer the first controlled object 560 becomes to a two-inertial frame of reference. In this way, the first controlled object 560 is composed of two inertial frames of reference.

[0022] The control device 100 is electrically connected to the inverter 545. Based on detection signals detected by the steering torque sensor 541, the steering angle sensor 542, and the vehicle speed sensor 300 mounted on the vehicle V, the control device 100 generates a motor drive signal and outputs it to the inverter 545. The control device 100 controls the first controlled object 560 by controlling the rotation of the motor 543 via the inverter 545. More specifically, the control device 100 controls the switching operation of multiple switching elements in the inverter 545. Specifically, the control device 100 generates a control signal to control the switching operation of each switching element and outputs it to the inverter 545. Each switching element is, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). In the following description, the control signal that controls the switching operation of each switching element will be called a "gate control signal".

[0023] The control device 100 controls the steering torque T h A torque command value is generated based on these factors, and the torque and rotational speed of the motor 543 are controlled, for example, by vector control. Vector control is a method of decomposing the current flowing through the motor 543 into a current component that contributes to torque generation and a current component that contributes to magnetic flux generation, and independently controlling each mutually orthogonal current component. The control device 100 is not limited to vector control and can perform other closed-loop control methods. The rotational speed of the motor 543 is expressed, for example, as the number of revolutions per minute [rpm (revolutions per minute)] or the number of revolutions per second [rps (revolutions per second)].

[0024] Furthermore, the control device 100 receives the steering torque T directly from the steering torque sensor 541. h The value may be input, or the control device 100 may input the steering torque T from the output value of the steering torque sensor 541. h The value of may be calculated. The steering angle sensor 542 detects the rotation angle θ of the input shaft 524a. aThe control device 100 may also detect the steering angle θ of the steering wheel 521 directly from the steering angle sensor 542. h The value may be input, or the control device 100 may input the steering angle θ from the output value of the steering angle sensor 542. h You may also calculate the value of .

[0025] In this embodiment, the electric power steering system 1000 includes a motor unit 100a. The motor unit 100a includes a control device 100, a motor 543, and an inverter 545. The motor unit 100a can be manufactured and sold independently of the other parts of the electric power steering system 1000. Furthermore, the control device 100 can be manufactured and sold independently of the other parts of the motor unit 100a as a control device for controlling the electric power steering system 1000.

[0026] Figure 2 shows a typical configuration of the control device 100 in this embodiment. The control device 100 includes, for example, a power supply circuit 111, an angle sensor 112, an input circuit 113, a communication interface 114, a drive circuit 115, a ROM 116, and a processor 200. The control device 100 can be implemented as a printed circuit board (PCB) on which these electronic components are mounted.

[0027] The processor 200 is connected to the vehicle speed sensor 300, steering torque sensor 541, and steering angle sensor 542, all mounted on the vehicle V, so that they can input signals to the processor 200. The vehicle speed is input to the processor 200 from the vehicle speed sensor 300. The steering torque T is input to the processor 200 from the steering torque sensor 541. h The following is input: The processor 200 receives the steering angle θ from the steering angle sensor 542. h The following is entered.

[0028] The processor 200 is a semiconductor integrated circuit, also known as a central processing unit (CPU) or microprocessor. The processor 200 sequentially executes a computer program stored in the ROM 116, which contains instructions for controlling the motor drive, to achieve the desired processing. In addition to the processor 200, or in place of the processor 200, the control device 100 may have an FPGA (Field Programmable Gate Array) equipped with a CPU, a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), an ASSP (Application Specific Standard Product), or a combination of two or more circuits selected from these circuits. The processor 200 sets a current command value according to the actual current value and the rotation angle of the motor 543 rotor, generates a PWM (Pulse Width Modulation) signal, and outputs the PWM signal to the drive circuit 115.

[0029] The power supply circuit 111 is connected to an external power supply (not shown). The power supply circuit 111 generates the DC voltage required for each part of the control device 100. The DC voltage generated by the power supply circuit 111 is, for example, 3V or 5V.

[0030] The angle sensor 112 measures the rotation angle θ of the rotor of the motor 543. m The rotation angle θ is detected and output to the processor 200. In this embodiment, the rotation angle θ m This is the "first output value" indicating the output of the motor 543. The angle sensor 112 may be a resolver, a Hall element such as a Hall IC, or an MR sensor having a magnetoresistive element. The processor 200 can calculate the angular velocity ω [rad / s] of the motor 543 based on the electrical angle of the motor 543 obtained from the angle sensor 112. The control device 100 may also be equipped with a speed sensor capable of detecting the rotational angular velocity of the motor 543 and an acceleration sensor capable of detecting the rotational angular acceleration of the motor 543 instead of the angle sensor 112.

[0031] The input circuit 113 receives the motor current value detected by a current sensor (not shown). In the following description, the motor current value detected by the current sensor (not shown) will be referred to as the "actual current value". The input circuit 113 converts the level of the input actual current value to the input level of the processor 200 as needed, and outputs the actual current value to the processor 200. A typical example of the input circuit 113 is an analog-to-digital conversion circuit.

[0032] Communication I / F114 is an input / output interface for transmitting and receiving data in accordance with, for example, an in-vehicle control area network (CAN: Controller Area Network).

[0033] The drive circuit 115 is typically a gate driver or pre-driver. The drive circuit 115 generates gate control signals according to the PWM signal and applies gate control signals to the gates of the multiple switching elements of the inverter 545. For example, when the motor 543 to be driven is a motor that can be driven at a low voltage, the drive circuit 115 as a gate driver may not be necessary. In that case, the gate driver function of the drive circuit 115 can be implemented in the processor 200.

[0034] ROM116 is electrically connected to processor 200. ROM116 is, for example, writable memory, rewritable memory, or read-only memory. Examples of writable memory include PROM (Programmable Read Only Memory). Examples of rewritable memory include flash memory and EEPROM (Electrically Erasable Programmable Read Only Memory). ROM116 stores a control program containing instructions for processor 200 to control motor drive. For example, the control program stored in ROM116 is temporarily loaded into RAM (not shown) during boot-up.

[0035] As shown in Figure 3, the lane keeping system 1100 is comprised of a control device 100 and an imaging device 400. The lane keeping system 1100 is a system for keeping a human-driven vehicle V in the center of a lane L. Based on the image of the lane L captured by the imaging device 400, the lane keeping system 1100 controls the steering mechanism 530 via the control device 100 to return the vehicle V to the center of the lane L if the vehicle V is about to deviate from the center of the lane L. The imaging device 400 is mounted, for example, on the windshield FG of the vehicle V.

[0036] As shown in Figure 4, the imaging device 400 includes an imaging device body 410 and an imaging device control unit 420. The imaging device body 410 images the portion of the lane L located in front of the vehicle V. The imaging device body 410 is, for example, a camera having a CCD (Charge Coupled Device) image sensor. The imaging device control unit 420 controls the imaging device body 410. The imaging device control unit 420, like the processor 200, is a semiconductor integrated circuit. Based on the image captured by the imaging device body 410, the imaging device control unit 420 outputs target coordinates x,y.

[0037] FIG. 4 shows an example of the functional blocks of the processor 200 of the present embodiment. The processor 200, which is a computer, sequentially executes processes or tasks necessary for controlling the steering mechanism 530 using each functional block. Each functional block of the processor 200 shown in FIG. 4 may be implemented in the processor 200 as software such as firmware, may be implemented in the processor 200 as hardware, or may be implemented in the processor 200 as software and hardware. The processing of each functional block in the processor 200 is typically described in a computer program in units of software modules and stored in the ROM 116. However, when using an FPGA or the like, all or part of these functional blocks may be implemented as a hardware accelerator. Further, the control method of the first control target 560 in the present embodiment is executed by a program stored in the control device 100 being executed by the processor 200, which is a computer. That is, the program of the present embodiment stored in the control device 100 causes the processor 200, which is a computer, to execute the control method of the first control target 560 of the present embodiment. Also, in the present embodiment, the control device 100 stores a program that causes the processor 200, which is a computer, to execute the control method of the second control target 580, which will be described later.

[0038] The processor 200 includes a controller 201, a subtractor SU1, and a torque converter 223. The controller 201 includes a first assist control unit 210, a second assist control unit 220, a vehicle stabilization control unit 240, a disturbance sensitivity control unit 290, a first gain adjustment unit 610, a second gain adjustment unit 620, and an adder AD5. That is, the control device 100 includes the first assist control unit 210, the second assist control unit 220, the vehicle stabilization control unit 240, the disturbance sensitivity control unit 290, the first gain adjustment unit 610, the second gain adjustment unit 620, and the adder AD5. In other words, functions corresponding to the first assist control unit 210, the second assist control unit 220, the vehicle stabilization control unit 240, the disturbance sensitivity control unit 290, the first gain adjustment unit 610, the second gain adjustment unit 620, and the adder AD5 are implemented in the processor 200 of the control device 100.

[0039] The first assist control unit 210 is capable of performing lane keeping control for maintaining the vehicle V within the lane L. As shown in FIG. 5, the first assist control unit 210 includes a vehicle state calculation unit 211, a calculation unit 212, a first generation unit 213, a second generation unit 210a, a selection processing unit 210d, and a vehicle characteristic compensation unit 210e, and a correction unit 210f. The vehicle state calculation unit 211 calculates a yaw rate target value γ r , which is the target value of the yaw rate γ of the vehicle V, and a lateral deviation y of of the vehicle V based on the input from the imaging device 400. The yaw rate target value γ r is the yaw rate γ required for the vehicle V not to deviate from the lane L.

[0040] The yaw rate γ in vehicle V is a parameter that indicates the change in the yaw angle φ, which is the angle of lateral movement of vehicle V. In other words, the yaw rate γ is the angular velocity when vehicle V moves from side to side. In the example shown in Figure 3, in a lane L with a curve to the left, vehicle V before turning the curve is shown by a solid line, and vehicle V after turning the curve is shown by a dashed line. The angle formed by the imaginary line CL1 extending in the direction of travel of vehicle V (shown by the solid line) and the imaginary line CL2 extending in the direction of travel of vehicle V (shown by the dashed line) is the change in the yaw angle φ when vehicle V turns the curve. Note that the imaginary lines CL1 and CL2 coincide with the optical axis of the imaging device body 410 when viewed from, for example, above in the vertical direction. The optical axis of the imaging device body 410 passes through the center in the left-right direction of the region IR imaged by the imaging device body 410.

[0041] Figure 6 shows the xy coordinate system. The x-axis is an axis extending in one direction horizontally. The y-axis is an axis extending in one direction horizontally and perpendicular to the x-axis. Figure 6 shows an example of a vehicle V moving in the x-axis direction and curving in the y-axis direction. In a vehicle V moving in the x-axis direction, the lateral deviation y of The target path R t This is the amount of displacement of the vehicle V in the y-axis direction relative to (x). Target path R t (x) is the center of gravity V of the vehicle V. g This is the target path that the vehicle will take, and it lies on the center line LCL of lane L. The x and y coordinate positions of vehicle V shown in Figure 6 are the center of gravity V of vehicle V. g Let this be the x and y coordinate position. In other words, the lateral displacement y of The target path R t (x) and centroid V g This is the distance in the y-axis direction between the two points. Note that at the position of vehicle V shown in Figure 6, the center of gravity V g The x and y coordinates are (0,0).

[0042] The vehicle state calculation unit 211 calculates the yaw rate target value γ based on the target coordinates x and y input from the imaging device 400. r and lateral displacement y of The vehicle state calculation unit 211 calculates the coordinates (x) from the imaging device 400. k-1,y k-1 ) and coordinates (x k ,y k ) and coordinates (x k+1 ,y k+1 Three target coordinate (x,y) values ​​are input. The three target coordinate (x,y) values ​​are the target path R on the target centerline LCL. t These are the coordinates included in (x). Coordinates (x k-1 ,y k-1 ) is the target path R at the current x-axis position of vehicle V. t This is the coordinate on (x). Coordinate (x k+1 ,y k+1 ) is the target path R at an x-axis position forward of the current x-axis position of vehicle V. t This is the coordinate on (x). Coordinate (x k ,y k ) is the coordinate (x k-1 ,y k-1 The x-axis position and coordinates (x k+1 ,y k+1 Target path R at the x-axis position of the center between the x-axis position of ) t This is the coordinate on (x). Target path R t (x) is the target y-axis position relative to the x-axis position. Target path R t (x) can be expressed, for example, as shown in equation (1) below.

[0043]

number

[0044] The vehicle state calculation unit 211 uses three coordinates (x k-1 ,y k-1 ),(x k ,yk ), (x k+1 , y k+1 ) is substituted into the following formula (2) to calculate the value of each term in formula (1). As a result, the lateral deviation y of is calculated.

[0045]

Number

[0046] The vehicle state calculation unit 211 substitutes the change rate C rp , the curvature C p , and the coordinates x k-1 , x k+1 into the following formula (3) to calculate the radius of curvature R k-1 , y k-1 ) of the target path R t (x) at the coordinates (x c (x k-1 ).

[0047]

Number

[0048] The vehicle state calculation unit 211 substitutes the radius of curvature R c (x k-1 ) obtained based on the above formula (3) into the following formula (4) to calculate the yaw rate target value γ r .

[0049]

Number

[0050] As described above, the vehicle state calculation unit 211 calculates the yaw rate target value γ r and the lateral deviation y of . As shown in FIG. 5, the yaw rate target value γ r and the lateral deviation y ofis input to the calculation unit 212 and the second generation unit 210a.

[0051] The calculation unit 212 calculates a target steering angle θ r based on the input yaw rate target value γ of and the lateral deviation y sr . The target steering angle θ sr is the steering angle θ r required to make the yaw rate γ equal to the yaw rate target value γ of and to converge the lateral deviation y s to zero, and is the steering angle θ s required to prevent the vehicle V from deviating from the lane L. In the present embodiment, the target steering angle θ sr is the target value of the output of the reduction mechanism 544. The target steering angle θ sr calculated by the calculation unit 212 is input to the first generation unit 213. More specifically, the target steering angle θ sr is input to a subtracter SU7, which will be described later, of the first generation unit 213.

[0052] Based on the target value of the output of the reduction mechanism 544, that is, the target steering angle θ sr , the first generation unit 213 generates a first command torque T LKA . In the present embodiment, the first command torque T LKA is the "first input value" generated by the first assist control unit 210. The steering angle θ s is fed back to the first generation unit 213. In the present embodiment, the steering angle θ s is the "second output value" indicating the output of the reduction mechanism 544. The first generation unit 213 generates the first command torque T LKA by, for example, PD (Proportional-Differential) control. The first generation unit 213 includes a compensation unit 214 and a torque calculation unit 215.

[0053] The compensation unit 214 receives the steering angle θ sis input. The compensation unit 214 performs a phase delay compensation process on the phase delay that occurs in the feedback steering angle θ s The compensation unit 214 includes a phase delay element 216 and a subtractor SU7. The phase delay element 216 delays the phase of the steering angle θ s fed back to the first generation unit 213. The steering angle θ s is input to the phase delay element 216. The transfer function C fp (s) of the phase delay element 216 is expressed by, for example, the following equation (5).

[0054]

Equation

[0055] The output from the phase delay element 216 is input to the subtractor SU7. The subtractor SU7 subtracts the output of the phase delay element 216 from the target steering angle θ sr and outputs it to the torque calculation unit 215. The torque calculation unit 215 calculates a first command torque T sr based on the target steering angle θ LKA input from the subtractor SU7. The first command torque T LKA is the torque required to make the steering angle θ s equal to the target steering angle θ sr In this embodiment, the torque calculation unit 215 adds the value obtained by multiplying the target steering angle θ sr by the proportional gain K P in proportional control (P control) and the value obtained by multiplying the differentiated target steering angle θ sr by the differential gain K D in differential control (D control) to calculate the first command torque T LKA The first command torque T LKA calculated by the torque calculation unit 215 is input to the selection processing unit 210d.

[0056] In the compensation unit 214, the steering angle θ is phase-delayed by the phase-delay element 216. s The target steering angle θ is determined by the subtractor SU7. sr By subtracting from the steering angle θ, s The phase can be advanced, and the steering angle θ s The phase lag that occurs can be compensated for. This is because the phase lag caused by the phase lag element 216 is inverted by subtracting it with the subtractor SU7, resulting in the effect of a phase lead.

[0057] First command torque T LKA This can be expressed, for example, by the following equation (6). Also, if disturbances are ignored, the steering angle θ s This can be simply expressed by the following equation (7).

[0058]

number

[0059]

number

[0060] Steering torque T is assumed to be in a state where no force is applied to the steering wheel 521. hIf we set to zero, then from equations (6) and (7) above, the target steering angle θ sr From steering angle θ s Transfer function θ up to s / θ sr This can be expressed as shown in equation (8) below.

[0061]

number

[0062] From equation (8) above, the transfer function C of the phase lag element 216 fp By making (s) a phase lag element, the target steering angle θ sr From steering angle θ s Transfer function θ up to s / θ sr In this case, it can be seen that the effect of phase advance is obtained. Note that K in equation (8) above P C L (s)P m Since (s) is a lag element, it can be approximated by, for example, a first-order phase lag element. K P C L (s)P m (s) is approximated by a first-order phase lag element, and the transfer function C fp By substituting equation (5) above into (s) and verifying the response of the resulting equation using a Bode plot, it can be confirmed that the phase lead effect is obtained.

[0063] The second generation unit 210a generates the first command torque T based on the output from the vehicle state calculation unit 211. LKA The second generation unit 210a includes a yaw rate control unit 210b, a lateral displacement control unit 210c, and an adder AD2. The yaw rate control unit 210b is configured to generate a yaw rate target value γ. r Vehicle V's travel speed V v , and coordinates (x k+1 ,y k+1 ) Target path R t Curvature C of (x) p The input values ​​are entered. The yaw rate control unit 210b generates a yaw rate command torque T based on these input values. γIt generates the lateral displacement control unit 210c, which receives the lateral displacement y of The input is received. The lateral displacement control unit 210c receives the lateral displacement y of Based on the lateral displacement command torque T y The yaw rate command torque T output from the yaw rate control unit 210b is generated. γ And the lateral displacement command torque T output from the lateral displacement control unit 210c y This means that the two values ​​are added together in adder AD2, and the first command torque T LKA It is output as follows: The first command torque T generated in the second generation unit 210a LKA This is input to the selection processing unit 210d.

[0064] The selection processing unit 210d receives the first command torque T from the first generation unit 213 and the second generation unit 210a, respectively. LKA The following is input. The selection processing unit 210d receives the first command torque T input from the first generation unit 213. LKA and the first command torque T input from the second generation unit 210a LKA The first command torque T LKA The selection processing unit 210d performs a process to select whether to adopt the selected option. For example, in the calculation unit 212, the target steering angle θ sr If it is possible to generate it, the first command torque T input from the first generation unit 213 LKA This is adopted, and otherwise the first command torque T input from the second generation unit 210a is used. LKA The selected first command torque T is adopted. The selection processing unit 210d selects the first command torque T LKA This is output to the vehicle characteristics compensation unit 210e.

[0065] The vehicle characteristic compensation unit 210e controls the steering angle θ h This part compensates for the vehicle characteristics based on the relationship between the steering mechanism 530 and the yaw rate γ, which indicates the change in the yaw angle φ of the vehicle V on which the steering mechanism 530 is installed. These vehicle characteristics are related to the steering angle θ h This is the transfer characteristic when the input is and the output is the yaw rate γ. The transfer function of the vehicle characteristic compensation unit 210e is, for example, a transfer function that can cancel out the vehicle characteristics. The first command torque T with vehicle characteristics compensated in the vehicle characteristic compensation unit 210e.LKA This is input to the correction unit 210f. The correction unit 210f is the part that performs corrections considering the mechanical characteristics of the helmsman's arm. The correction unit 210f receives the first command torque T output from the vehicle characteristic compensation unit 210e. LKA The first command torque T corrected in the correction unit 210f is corrected. LKA This is output from the first assist control unit 210.

[0066] The target steering angle θ input to the first generation unit 213 is also input. sr This may be a value input to the control device 100 from outside the control device 100. Target steering angle θ sr This may, for example, be input from the imaging device 400 to the first generation unit 213. Target steering angle θ sr When the target steering angle θ is input to the first generation unit 213 from outside the control device 100, the first generation unit 213 receives the target steering angle θ from outside the control device 100. sr Based on the first command torque T LKA Either generate the target steering angle θ calculated by the calculation unit 212. sr Based on the first command torque T LKA You may choose whether to generate it. Target steering angle θ sr When the target steering angle θ is input to the first generation unit 213 from outside the control device 100, the first generation unit 213 receives the target steering angle θ from outside the control device 100. sr and the target steering angle θ calculated in the calculation unit 212 sr Based on the average value, the first command torque T LKA You may generate the target steering angle θ. sr When the target steering angle θ is input to the first generation unit 213 from outside the control device 100, the calculation unit 212 is not provided and the first assist control unit 210 does not input the target steering angle θ sr It is not necessary for it to be generated. For example, the target steering angle θ sr When the first command torque T is input to the first generation unit 213 from outside the control device 100, the selection processing unit 210d receives the first command torque T from the first generation unit 213. LKA We will adopt this.

[0067] As shown in Figure 4, the first command torque T output from the first assist control unit 210 LKA This is input to the first gain adjustment unit 610. The first gain adjustment unit 610 controls the first command torque T LKA The gain is adjusted. The first gain adjustment unit 610 adjusts the first command torque T LKA Multiplying this by the first gain K1, the first command torque T is obtained. LKA1 The output is as follows. The first gain K1 is a variable value. The first gain K1 is expressed as K1 = 1 - K2 using the second gain K2 of the second gain adjustment unit 620. First command torque T LKA1 This is input to the adder AD5 and the vehicle stabilization control unit 240.

[0068] The subtractor SU1 receives the steering angle θ detected based on the steering angle sensor 542. h The input is: Subtractor SU1 calculates the steering angle θ. h Based on the steering torque sensor 541 and the steering angle sensor 542, the steering angle θ is detected. s This value is subtracted and output to the torque conversion unit 223.

[0069] The torque conversion unit 223 receives the value output from the subtractor SU1. The torque conversion unit 223 multiplies the value output from the subtractor SU1 by a gain to obtain the steering torque T h The output is the spring constant K of the torsion bar 546. The gain in the torque conversion unit 223 is the spring constant K of the torsion bar 546. tor It is equal to the steering angle θ. h and steering angle θ s The difference is the spring constant K of the torsion bar 546. tor The value obtained by multiplying by this is the torsion bar torque, or steering torque T. h Steering torque T h This is input to the second gain adjustment unit 620.

[0070] The second gain adjustment unit 620 controls the steering torque T h The gain of the steering torque T is adjusted. The second gain adjustment unit 620 adjusts the steering torque T. h Multiplying this by the second gain K2, the steering torque T h1The output is as follows. The second gain K2 is greater than or equal to 0 and less than or equal to 1. The second gain K2 is the steering torque T h This is a variable value that changes depending on the value of K1. From the relationship K1 = 1 - K2 described above, when the second gain K2 is 1, the first gain K1 is 0; when the second gain K2 is 0.5, the first gain K1 is 0.5; and when the second gain K2 is 0, the first gain K1 is 1. The larger the value of the second gain K2, the greater the steering torque T input by the helmsman via the steering wheel 521. h The effect becomes greater, and the larger the value of the first gain K1, the greater the first command torque T output from the first assist control unit 210. LKA The effect becomes greater. The first gain K1 when the first assist control unit 210 performs lane keeping control is greater than the first gain K1 when the first assist control unit 210 does not perform lane keeping control. Steering torque T output from the second gain adjustment unit 620 h1 This is input to adder AD5. Adder AD5 processes the steering torque T h1 The first command torque T LKA1 The result is added and output to the second assist control unit 220.

[0071] The second assist control unit 220 inputs a second command torque T to the vehicle stabilization control unit 240 based on the steering input value input from the steering wheel 521 of the vehicle V. r This generates the steering input value, which is the steering torque T. h In this embodiment, the second command torque T r This is the "second input value" generated by the second assist control unit 220. The second assist control unit 220 controls the second command torque T r By generating a reaction force and controlling the torque of the motor 543, the reaction force transmitted to the helmsman from the steering wheel 521 is controlled. As shown in Figure 7, the second assist control unit 220 includes a base assist control unit 221 and a phase compensator 222.

[0072] The base assist control unit 221 controls the torsion bar torque generated in the torsion bar 546, i.e., the steering torque T. h Input torque T calculated based onad Based on this, the self-aligning torque T generated in the vehicle's tires 529A and 529B SAT Assist torque T that compensates for at least a portion of it ass In this embodiment, the base assist control unit 221 generates the steering torque T. h Steering torque T is multiplied by a second gain K2. h1 and the first command torque T LKA The first command torque T is multiplied by the first gain K1. LKA1 The input torque T is calculated by adding these together. ad Based on, Assist Torque T ass Generates.

[0073] In this embodiment, the base assist control unit 221 controls the input torque T ad Assist Gain K ass Multiply by the assist torque T ass The output is shown in Figure 8. Input torque T ad and Assist Torque T ass An example of the relationship is shown. In the graph in Figure 8, the horizontal axis is the input torque T. ad The vertical axis represents the assist torque T. ass This indicates the input torque T ad Assist torque T ass The slope of the assist gain K ass This is the input torque T. ad and Assist Torque T ass and assist gain K ass That is, dT ass / dT ad =K ass The relationship is satisfied. As shown in Figure 8, the assist torque T ass For example, input torque T ad As the value increases, it increases exponentially. As shown in Figure 7, the assist torque T output from the base assist control unit 221 ass This is input to the phase compensator 222.

[0074] Furthermore, the base assist control unit 221 controls the input torque T ad and the travel speed of vehicle V vBased on the assist torque T ass The base assist control unit 221 may generate, for example, the input torque T ad and driving speed V v and Assist Torque T ass It has a lookup table (LUT) that defines the relationship with and refers to the assist torque T ass You may decide that.

[0075] In this embodiment, the phase compensator 222 adjusts the gain within the range of steering frequencies that the helmsman can take when operating the steering wheel 521, and compensates for the rigidity of the torsion bar 546. The range of steering frequencies that can take is, for example, 5 Hz or less. When the steering frequency is 5 Hz or less, the phase compensator 222 adjusts the assist torque T ass For example, first-order phase compensation may be applied. First-order phase compensation is represented, for example, by the transfer function C(s) of equation (9).

[0076]

number

[0077] The phase compensator 222 outputs the assist torque T from the base assist control unit 221. ass And the second command torque T based on the gain of the phase compensator 222 r This generates the second command torque T, which is the second input value. r , Assist Torque T ass It is calculated based on the following. For example, the phase compensator 222 is a stabilizer compensator, and the assist torque T assStability phase compensation can be applied to this. The phase compensator 222 may have a second-order or higher transfer function whose frequency characteristics are variable depending on the gain of the transfer function C(s). A second-order or higher transfer function is expressed using response parameters and damping parameters. A second-order or higher transfer function C(s) can be expressed, for example, by equation (10). By making the order of the transfer function C(s) second-order, damping can be applied to the characteristics of the transfer function C(s). By changing the damping, it is possible to adjust the phase characteristics.

[0078]

number

[0079] In equation (10), s is a Laplace transformer, ω3 is the zero frequency of the transfer function C(s), ω4 is the pole frequency of the transfer function C(s), ζ3 is the zero attenuation ratio, and ζ4 is the pole attenuation ratio. The pole frequency ω4 is lower than the zero frequency ω3.

[0080] As shown in Figure 4, the vehicle stabilization control unit 240 receives the first command torque T output from the first gain adjustment unit 610. LKA1 Then, the second command torque T output from the second assist control unit 220 r The following is input. As shown in Figure 9, the vehicle stabilization control unit 240 includes a second model following control unit 241, a second state feedback unit 242, a subtractor SU5, and an adder AD6.

[0081] The subtractor SU5 receives the first command torque T LKA1 and the second command torque T r The command torque T is the sum of the two. rL The input is T. The subtractor SU5 receives the input command torque T. rL From there, the second corrected torque T output from the second model following control unit 241 f2Subtract the value. The output from the subtractor SU5 is input to the adder AD6 and the second model following control unit 241. The adder AD6 outputs the command torque T, which is the value obtained by adding the output from the second state feedback unit 242 to the output from the subtractor SU5. rL1 The command torque T is output to the disturbance sensitivity control unit 290. In this embodiment, the command torque T rL1 This is the first command torque T multiplied by the first gain K1. LKA1 and the second command torque T multiplied by the second gain K2 r This is the "command value" calculated based on [the specified criteria].

[0082] In this embodiment, the second model following control unit 241 is a controller configured to perform model following control. The second model following control unit 241 controls the command torque T rL Second correction torque T to correct for f2 The second corrected torque T is generated based on the yaw rate γ and the second nominal model NM2. In this embodiment, the second corrected torque T f2 is the commanded torque T rL This is the feedback torque that is fed back. The second nominal model NM2 is an internal model used as a model that constrains the second controlled object 580 when controlling the second controlled object 580. In this embodiment, the second controlled object 580 is the actual steering angle θ of the tires 529A and 529B. t This is a plant model that takes as input and outputs yaw rate γ. t This is the angle at which the tires 529A and 529B tilt in the left-right direction relative to the longitudinal direction of the vehicle body V, when viewed in the vertical direction. The second controlled object 580 shown in Figure 9 is the vehicle V. Transfer function G of the second controlled object 580 θ γ (s) is determined by the characteristics of vehicle V.

[0083] In this embodiment, the second model following control unit 241 calculates a second corrected torque T based on the yaw rate γ. f2 Generates command torque T rLThe second model following control unit 241 includes a second inverse nominal model 243, a filter 244, a torque conversion unit 245, and a subtractor SU6.

[0084] The second model following control unit 241, in a frequency band where the gain in the gain characteristic of the complementary sensitivity function for the modeling error between the plant model, the second controlled object 580, and the second nominal model NM2 is approximately 1, sets the transfer function of the second controlled object 580 to the transfer function P of the second nominal model NM2. nv It is configured to be constrained by (s).

[0085] In this specification, "the transfer function of a controlled object is constrained to the transfer function of a nominal model" means, for example, that the controlled object is controlled such that, when looking at the input / output relationship, its transfer function appears to be the transfer function of a nominal model. Also, in this specification, "a certain gain is approximately 1" includes not only the case where a certain gain is 1, but also, for example, the case where a certain gain is 0.8 or more and 1.2 or less. This numerical range is, for example, the range in which the gain of the effective disturbance suppression characteristic can be adjusted to 1 when the reduction mechanism 544 connected to the motor 543 has a worm gear, taking into account the positive and negative efficiency of the worm gear. Since the efficiency of the worm gear is about 0.8, it is necessary to adjust the gain by ±0.2 relative to the target value of 1.

[0086] The complementary sensitivity function for the modeling error between the second controlled object 580 and the second nominal model NM2 is the complementary sensitivity function of the inner loop composed of the second model following control unit 241. In this embodiment, the complementary sensitivity function in the second model following control unit 241 is equal to the transfer function Q3(s) of the filter 244. The transfer function Q3(s), which is the complementary sensitivity function, has a gain of approximately 0 dB, i.e., a gain of approximately 1 in the frequency band through which the filter 244 passes. In other words, in this embodiment, the second model following control unit 241 controls the transfer function G of the second controlled object 580 in the frequency band where the gain in the gain characteristic of the transfer function Q3(s) is approximately 1. θ γ (s) is the transfer function P of the second nominal model NM2. nv It is configured to be constrained by (s). In this way, the vehicle stabilization control unit 240 controls the transfer function G of the second controlled object 580, which is a plant model. θ γ (s) is the transfer function P of a predetermined second nominal model NM2 by model following control performed by the second model following control unit 241. nv (s) is constrained.

[0087] The second inverse nominal model 243 is the inverse model of the second nominal model NM2 used to constrain the second controlled object 580. The transfer function P of the second nominal model NM2. nv (s) is expressed, for example, by the following equation (11): Transfer function P of the second inverse nominal model 243 nv -1 (s) is expressed by the following equation (12).

[0088]

number

[0089]

number

[0090] Transfer function P of the second nominal model NM2 nv The gain at (s) is represented, for example, as shown in Figure 10. As shown in Figure 10, the transfer function P of the second nominal model NM2 nv The gain at (s) is equal to the natural frequency f of the yaw rate γ. γ The parameter f corresponds to this parameter. n Steady-state gain G in the following frequency band θ γ (0), parameter f n The reduction occurs in higher frequency bands. For example, in the first assist control unit 210, the yaw rate target value γ r A predetermined frequency f d By reducing the gain in the above frequency band, the transfer function P of the second nominal model NM2 is achieved. nv The gain at (s) is the steady-state gain G θ γ In the region where (0), the second control target 580 can be controlled. The predetermined frequency f d This is a parameter f set by model following control in the vehicle stabilization control unit 240. n It is a lower frequency than that.

[0091] The second inverse nominal model 243 receives the output of the second controlled object 580, i.e., the yaw rate γ, as input. The second inverse nominal model 243 generates the rudder angle θ based on equation (12) above and the input yaw rate γ. tp Outputs the rudder angle θ. tp This refers to the actual steering angle θ input to the second nominal model NM2 when the output value of the second controlled object 580 is the same as the output value of the second controlled object 580. t It is equal to the value of the rudder angle θ. tp This is input to the torque conversion unit 245. The torque conversion unit 245 controls the steering angle θ tp Torque Tp2 Convert and output.

[0092] The subtractor SU6 subtracts the output of the subtractor SU5 from the output of the torque conversion unit 245 to obtain the differential torque T. a2 The differential torque T output from subtractor SU6 is generated. a2 This is input to filter 244. Filter 244 processes the differential torque T a2 The second corrected torque T is then filtered. f2 The output is then sent to the subtractor SU5.

[0093] The second model following control unit 241 constrains the second controlled object 580 to the second nominal model NM2, thereby controlling the natural frequency f of the yaw rate γ. γ The transfer function P of the second nominal model NM2 nv Parameter f in (s) n It can be restrained.

[0094] The second state feedback unit 242 receives the yaw rate γ or steering angle θ of the vehicle V. s Based on this, a state feedback torque T is used to approximate the characteristics of the vehicle V to a first-order lag transfer function. fb It outputs the state feedback torque T. As shown in Figure 11, the second state feedback unit 242 has a yaw rate conversion unit 242a, a switch unit 242b, and a torque conversion unit 242c. The switch unit 242b outputs the state feedback torque T. fb The yaw rate γ of the vehicle V and the steering angle θ s The system switches which of the two is used for calculation. If there is a signal from the imaging device 400, the switch unit 242b outputs the yaw rate γ calculated based on the imaging device 400 to the torque conversion unit 242c. If there is no signal from the imaging device 400, the switch unit 242b outputs the steering angle θ s The yaw rate γ calculated based on this is output to the torque conversion unit 242c. The yaw rate conversion unit 242a receives the input steering angle θ. s This is converted to a yaw rate γ and output to the switch unit 242b. The transfer function of the yaw rate conversion unit 242a is G θγ (s) / g tot It is represented as G θ γ (s) is the actual rudder angle θ t This represents the transfer characteristics from yaw rate γ, and is the transfer function of the second controlled object 580. 1 / g tot is the steering angle θ s From the actual steering angle θ t This is the conversion gain up to g. tot is the steering angle θ s From the actual steering angle θ t This parameter corresponds to the gear ratio up to [a certain point].

[0095] The torque conversion unit 242c converts the yaw rate γ input from the switch unit 242b into a state feedback torque T fb It is converted and output. The transfer function C1(s) of the torque conversion unit 242c is expressed by the following equation (13).

[0096]

number

[0097] As shown in Figure 9, the state feedback torque T output from the second state feedback unit 242 fbThis is input to adder AD6 and added to the output from subtractor SU5. Adder AD6 then applies a state feedback torque T to the output from subtractor SU5. fb Add to the command torque T rL1 The output is then sent to the disturbance sensitivity control unit 290.

[0098] The transfer function of the second controlled object 580 described above, i.e., the transfer function G of the characteristics of the vehicle V. θ γ (s) is expressed by the following equation (14).

[0099]

number

[0100] The second state feedback unit 242 controls the state feedback gain K d The state feedback torque T calculated by multiplying by fb By providing feedback, the damping ratio parameter ξ in equation (14) above can be controlled. When the damping ratio parameter ξ is set to 1 by the second state feedback unit 242, the right-hand term of equation (14) above can be approximated by a first-order lag transfer function as shown in equation (15) below.

[0101]

number

[0102] By approximating the transfer function of the second controlled object 580 as shown in equation (15) above, the transfer function P shown in equation (11) above can be used to approximate the second controlled object 580. nvIt becomes easier to constrain to the second nominal model NM2 having (s). Furthermore, by expressing the second nominal model NM2 with a first-order lag transfer function as shown in equation (11), even if the plant characteristics of the second controlled object 580 change, such as when the number of passengers in the vehicle V changes, the natural frequency f of the yaw rate γ can be controlled by the second nominal model NM2. γ The desired parameter f r This can be constrained. Thus, in this embodiment, by combining state feedback by the second state feedback unit 242 and model following control by the second model following control unit 241, stable and easy-to-steer vehicle V characteristics can be realized.

[0103] For example, by simply constraining the second controlled object 580 to the second nominal model NM2 using model following control, the natural frequency f of the yaw rate γ is obtained. γ Simply changing this will reduce robust stability if the modeling error between the second controlled object 580 and the second nominal model NM2 is large, and the natural frequency f of the yaw rate γ will decrease. γ In some cases, it may not be possible to adjust the desired characteristics. In this embodiment, the state feedback gain K of the second state feedback unit 242 in the vehicle stabilization control unit 240 addresses this issue. d By adjusting this, the transfer function G of the second controlled object 580 is as described above. θ γ By approximating (s) linearly, the transfer function G of the second controlled object 580 is obtained. θ γ (s) is the transfer function P of the second nominal model NM2 nv This allows us to approach (s) and reduce modeling errors. As a result, by performing model following control in the second model following control unit 241, we can obtain a stable and desirable natural frequency f of yaw rate γ. γ This can be achieved. The relationship between modeling error and robust stability in model following control will be explained in detail in the model following control by the first model following control unit 230, which will be described later.

[0104] As shown in Figure 12, the disturbance sensitivity control unit 290 receives the command torque T output from the vehicle stabilization control unit 240. rL1 The input is as follows: The disturbance sensitivity control unit 290 includes a first model following control unit 230, a first state feedback unit 280, an arithmetic unit 292, an adder AD3, and a subtractor SU2.

[0105] The first model following control unit 230 controls the command torque T rL1 The first corrective torque T corrects for the above. f1 This is generated based on the first nominal model NM1, which is based on the configuration of the first controlled object 560. In this embodiment, the first corrected torque T f1 This is the commanded torque T, which is the commanded value. rL1 This is a "correction value" that compensates for the command value. If the command value is an angle, the correction value is an angle. First corrected torque T f1 is the commanded torque T rL1 This is the feedback torque that is fed back to the system. The first nominal model NM1 is an internal model used as a model to constrain the first controlled object 560 when controlling the first controlled object 560. The first nominal model NM1 will be described in detail later. The first model following control unit 230 is a model following controller configured to perform model following control. The specific configuration of the first model following control unit 230 will be described in detail later.

[0106] The subtractor SU2 controls the commanded torque T rL1 From there, the first corrected torque T output from the first model following control unit 230 f1 Subtract the value. The output from the subtractor SU2 is input to the adder AD3 and the first model following control unit 230. The adder AD3 outputs the command torque T, which is the value obtained by adding the output from the first state feedback unit 280 to the output from the subtractor SU2. rL2 The output is sent to adder AD1. Adder AD1 receives the steering torque T from the output of adder AD3. h and disturbance torque T d The command torque T is the value obtained by adding the following: rL3The first controlled object 560 outputs the command torque T. rL3 The output is set to the steering angle θ. s This is the controlled object. As shown in Figure 9, the steering angle θ output from the first controlled object 560 s This is input to the conversion unit 570. The conversion unit 570 converts the steering angle θ s Multiply by the conversion gain 1 / gtot and the actual rudder angle θ t The output is the actual rudder angle θ output from the conversion unit 570. t This is input to the second control target 580. In Figure 4, the first control target 560, the conversion unit 570, and the second control target 580 are collectively shown as the control target block 590.

[0107] Disturbance Torque T d This is the difference between the output torque of the ideal motor 543 and the actual output torque of the motor 543. Disturbance torque T d This includes disturbance torque applied externally to the first controlled object 560. Disturbance torque T d This includes, for example, excess torque caused by friction and play resulting from mechanical elements such as the motor 543 and reduction mechanism 544, torque ripple in the motor 543, and self-aligning torque T. SAT This includes external disturbances such as torques that may occur when driving on unpaved, bumpy, or gravel roads.

[0108] As shown in Figure 12, in this embodiment, the first model following control unit 230 receives the third input value θ output from the calculation unit 292. i Based on the first corrected torque T f1 Generates command torque T rL1The first model following control unit 230 includes a first inverse nominal model 231, a first filter 232a, a second filter 232b, an assist adjustment unit 270, a subtractor SU3, and an adder AD4. In this embodiment, the first filter 232a is a high-pass filter. The first filter 232a has a first cutoff frequency Cf1. The first cutoff frequency Cf1 is, for example, 2Hz or more and 10Hz or less. In this embodiment, the first cutoff frequency Cf1 is higher than 5Hz and lower than 10Hz.

[0109] In this embodiment, the second filter 232b is a low-pass filter. The second filter 232b has a second cutoff frequency Cf2 that is higher than the first cutoff frequency Cf1. The second cutoff frequency Cf2 is, for example, 3 Hz or more and 50 Hz or less. However, the upper limit of the second cutoff frequency Cf2 may be set to a range of approximately 140 Hz or more and 200 Hz or less. The order of the second filter 232b is third order or higher. The second filter 232b may be composed of, for example, multiple low-pass filters. The first filter 232a and the second filter 232b are connected in series.

[0110] The first model following control unit 230 controls the transfer function P of the first control object 560 in a frequency band where the complementary sensitivity gain GT, which is the gain in the gain characteristic of the complementary sensitivity function T(s) for the modeling error between the first control object 560 and the first nominal model NM1, is approximately 1. s (s) is the transfer function P of the first nominal model NM1. sn It is configured to be constrained by (s).

[0111] The complementary sensitivity function T(s) is the complementary sensitivity function of the inner loop composed of the first model following control unit 230. Figure 13 shows the complementary sensitivity gain GT in the complementary sensitivity function T(s). The complementary sensitivity gain GT is the gain of the complementary sensitivity function T(s) as a transfer function, and is the absolute value of the complementary sensitivity function T(s). In the graph of Figure 13, the horizontal axis represents frequency f [Hz], and the vertical axis represents the complementary sensitivity gain GT. As shown in Figure 13, the complementary sensitivity function T(s) has a gain of approximately 0 dB, that is, the complementary sensitivity gain GT in the transfer function is approximately 1, in at least a portion of the frequency band where the frequency f is above the first cutoff frequency Cf1 and below the second cutoff frequency Cf2. In the example in Figure 13, the complementary sensitivity gain GT is 1 in the frequency band where the frequency f1a is higher than the first cutoff frequency Cf1 and below the second cutoff frequency Cf2 and below the second cutoff frequency Cf2. The frequency f1a is lower than the frequency f2a. In the frequency band between frequency f1a and frequency f2a, the complementary sensitivity gain GT may be, for example, a value of 0.95 or more and less than 1. The complementary sensitivity gain GT at the first cutoff frequency Cf1 is smaller than the complementary sensitivity gain GT at frequency f1a. The complementary sensitivity gain GT at the second cutoff frequency Cf2 is smaller than the complementary sensitivity gain GT at frequency f2a. In this embodiment, the frequency band in which the complementary sensitivity gain GT is approximately 1 is the frequency band between frequency f1b and frequency f2b. Frequency f1b is higher than the first cutoff frequency Cf1 and lower than frequency f1a. Frequency f2b is lower than the second cutoff frequency Cf2 and higher than frequency f2a. In the frequency band between frequency f1b and frequency f2b, the complementary sensitivity gain GT is, for example, 0.8 or more and less and less than 1.

[0112] Transfer function P of the first controlled object 560 s (s) is the plant characteristic on which model-following control is performed. Transfer function P of the first controlled object 560. s (s) can be expressed, for example, by the following equation (16).

[0113]

number

[0114] The first inverse nominal model 231 is the inverse model of the first nominal model NM1 used to constrain the first controlled object 560. The transfer function P of the first nominal model NM1. sn (s) is expressed, for example, by the following equation (17): Transfer function P of the first inverse nominal model 231 sn -1(s) can be expressed, for example, by the following equation (18).

[0115]

number

[0116]

number

[0117] In equations (17) and (18), s is the Laplace transformer, and J n is a parameter representing the moment of inertia of the first nominal model NM1, and B n This parameter represents the viscous friction coefficient of the first nominal model NM1. The transfer function P of the first nominal model NM1 is also shown. sn (s) and the transfer function P of the first inverse nominal model 231 sn -1 (s) is not limited to the examples shown in equations (17) and (18), and is not particularly limited.

[0118] As shown in Figure 12, the first inverse nominal model 231 has a third input value θ, which is the output from the calculation unit 292. i The following is input. In other words, in this embodiment, the first model following control unit 230 receives the third input value θ i The following is input. The first inverse nominal model 231 is given by equation (18) above and the input third input value θ. i Torque T based on p The output is calculated using the first nominal model NM1. p Calculate the torque T. p This value is equal to the torque input to the first nominal model NM1 when the output value of the first nominal model NM1 is the same as the output value of the first controlled object 560.

[0119] Subtractor SU3 subtracts the output of subtractor SU2 from the output of the first inverse nominal model 231 to obtain the differential torque T. aThis generates the first corrected torque T. f1 After the feedback is given, the state compensation value V described later is used. s Command torque T before it is fed back rL1 Torque T p Subtracting the difference torque T a Generates the differential torque T. a For example, disturbance torque T d This is an estimated value. The differential torque T output from subtractor SU3. a The signal is input to the second filter 232b, where it undergoes low-pass filtering, and then input to the first filter 232a, where it undergoes high-pass filtering. The differential torque T after filtering by the first filter 232a and the second filter 232b is then input to the first filter 232a and the second filter 232b. a This is input to adder AD4. The differential torque T filtered in the first filter 232a and the second filter 232b a This is a state in which frequency components lower than the first cutoff frequency Cf1 and frequency components higher than the second cutoff frequency Cf2 have been removed. In other words, the differential torque T filtered by the first filter 232a and the second filter 232b is... a This refers to frequency components T, which are above the first cutoff frequency Cf1 and below the second cutoff frequency Cf2. aM That is the case.

[0120] The assist adjustment unit 270 generates compensation values ​​for friction and disturbances, and adjusts the differential torque T a Adjusts the differential torque T. In this embodiment, the assist adjustment unit 270 adjusts the differential torque T. a Among them, frequency component T aM The assist adjustment unit 270 is coupled in parallel to the first filter 232a. The assist adjustment unit 270 includes a friction compensation value calculation unit 250, a disturbance compensation value calculation unit 260, and a subtractor SU4.

[0121] The subtractor SU4 subtracts the output value from the first filter 232a from the output value from the second filter 232b. Here, the output value from the second filter 232b is the differential torque T. aThis is the value after removing frequency components higher than the second cutoff frequency Cf2. The output value from the first filter 232a is the differential torque T a This is the value from which frequency components higher than the second cutoff frequency Cf2 and frequency components lower than the first cutoff frequency Cf1 have been removed. Therefore, the value output from the subtractor SU4 is the differential torque T a Among these, the frequency component T is lower than the first cutoff frequency Cf1. aL The output of the subtractor SU4 is input to the friction compensation value calculation unit 250 and the disturbance compensation value calculation unit 260. Frequency component T aL This includes frictional force and self-aligning torque T SAT This includes disturbance torque caused by play in the first controlled object 560, and torque ripple occurring in the first controlled object 560.

[0122] The friction compensation value calculation unit 250 calculates a friction compensation value V that compensates for at least a portion of the friction force generated in the first controlled object 560. f The difference torque T a The calculation is based on the following: As described above, the value from the subtractor SU4 input to the friction compensation value calculation unit 250 is the differential torque T a Among these, the frequency component T is lower than the first cutoff frequency Cf1. aL Therefore, in this embodiment, the friction compensation value calculation unit 250 calculates the differential torque T a Based on the component with a frequency lower than the first cutoff frequency Cf1, the friction compensation value V f Calculate.

[0123] The friction compensation value calculation unit 250 includes a limiter 252 and a gain adjuster 253. The limiter 252 limits the output value from the subtractor SU4. If the input value exceeds an upper or lower threshold, the limiter 252 clips the input value to the upper or lower threshold. The gain adjuster 253 multiplies the output value from the limiter 252 by a gain K3. The friction compensation value calculation unit 250 calculates the differential torque T a For the components with frequencies lower than the first cutoff frequency Cf1, the limiter 252 and the gain K3 are applied to obtain a friction compensation value V.f The threshold value of the limiter 252 and the gain K3 are predetermined, for example, based on the frictional force actually generated on the first controlled object 560.

[0124] Friction compensation value V output from friction compensation value calculation unit 250 f is the differential torque T a The frequency component T aL This value compensates for at least a portion of the frictional force component included in the first controlled object 560. Generally, a moderate amount of friction is required for the first controlled object 560, so the friction compensation value calculation unit 250 sets the friction compensation value V to a value smaller than the frictional force actually generated in the first controlled object 560. f This is calculated as follows. This makes it possible to achieve highly accurate friction compensation while leaving an appropriate amount of frictional force on the first controlled object 560. Friction compensation value V f The friction compensation provided by this system includes, for example, the friction of the motor 543, the friction of the reduction mechanism 544, and the difference in friction between the left and right sides of the reduction mechanism 544.

[0125] Vehicle V, equipped with an electric power steering system 1000, can be driven according to driving modes that include an automatic driving mode and a manual driving mode. In this case, the gain K3 of the gain adjuster 253 may be switched according to the driving mode. The larger the gain K3 of the gain adjuster 253, the greater the degree to which friction is reduced.

[0126] The disturbance compensation value calculation unit 260 calculates the self-aligning torque T generated in the first control target 560. SAT Disturbance compensation value V compensates for at least a portion of it. d The disturbance compensation value V is calculated in this embodiment. d This includes a compensation value that compensates for at least a portion of the frictional force generated in the first controlled object 560, the disturbance torque caused by the play in the first controlled object 560, and the torque ripple generated in the first controlled object 560. The disturbance compensation value calculation unit 260 calculates the torque T output from the first inverse nominal model 231. p and command torque T rL1 The difference is the differential torque T. aBased on this, the disturbance compensation value V d The disturbance compensation value calculation unit 260 calculates the torque T based on the output of the first controlled object 560 using the first nominal model NM1. p and command torque T rL1 The difference is the differential torque T. a Based on this, the disturbance compensation value V d The differential torque T is calculated. As described above, the value from the subtractor SU4 input to the disturbance compensation value calculation unit 260 is the differential torque T. a Among these, the frequency component is lower than the first cutoff frequency Cf1. Therefore, in this embodiment, the disturbance compensation value calculation unit 260 calculates the differential torque T a The disturbance compensation value V is based on the component with a frequency lower than the first cutoff frequency Cf1. d Calculate.

[0127] The disturbance compensation value calculation unit 260 includes a limiter 262 and a gain adjuster 263. The limiter 262 limits the output value from the subtractor SU4. If the input value exceeds an upper or lower threshold, the limiter 262 clips the input value to the upper or lower threshold. The threshold of the limiter 262 is different from, for example, the threshold of the limiter 252. The gain adjuster 263 multiplies the output value from the limiter 262 by a gain K4. Transfer function P of the first controlled object 560 s (s) is the transfer function P of the first nominal model NM1. sn The maximum value of the gain K4 of the gain adjuster 263 is determined under the constraint of (s). The value of gain K4 is different from, for example, the value of gain K3. In manual driving mode, the value of gain K4 is, for example, between 0.1 and 0.8. In automatic driving mode, the value of gain K4 is, for example, approximately 1. A value of approximately 1 for gain K4 includes a value of 0.8 or more and 1 or less. The gain K4 of the gain adjuster 263 may be switched according to the driving mode of the vehicle V.

[0128] Disturbance compensation value V d is the differential torque T a The frequency component T aLThis value compensates for at least a portion of the self-aligning torque component included in the disturbance compensation value calculation unit 260, for example, the self-aligning torque T that actually occurs in the first controlled object 560. SAT The disturbance compensation value V is approximately half of the value of the disturbance compensation value. d The self-aligning torque T that actually occurs in the first controlled object 560 is calculated as follows. SAT For example, the threshold value of the limiter 262 and the gain K4 of the disturbance compensation value calculation unit 260 are determined in advance by the self-aligning torque T in manual operation mode. SAT The disturbance compensation value V is set to a value between 0.1 and 0.8 times the magnitude of the disturbance. d The value is adjusted to the calculated value. The threshold value of the limiter 262 and the gain K4 of the disturbance compensation value calculation unit 260 are adjusted in advance to the self-aligning torque T in automatic driving mode. SAT The disturbance compensation value V is set to approximately 1 times the magnitude of the disturbance, i.e., a value between 0.8 times and 1 time. d The value is adjusted to the value at which the disturbance compensation value V is calculated in the disturbance compensation value calculation unit 260. d This is the friction compensation value V calculated in the friction compensation value calculation unit 250. f This is a different value.

[0129] Here, the differential torque T a The frequency component T aL This includes the frictional force generated in the first controlled object 560 and the self-aligning torque T generated in the first controlled object 560. SAT This includes disturbance torque caused by play in the first controlled object 560, and torque ripple occurring in the first controlled object 560. Therefore, the frequency component T aL The friction compensation value V obtained by processing with limiter 252 and gain adjuster 253 f This includes disturbances other than friction, namely the self-aligning torque T generated in the first controlled object 560. SAT This also includes compensation values ​​that compensate for at least a portion of the disturbance torque caused by the backlash in the first controlled object 560, and the torque ripple that occurs in the first controlled object 560. aLThe disturbance compensation value V obtained by processing with limiter 262 and gain adjuster 263 is obtained. d Self-aligning torque T SAT The compensation also includes compensation values ​​that compensate for other disturbances, namely frictional forces occurring in the first controlled object 560, disturbance torques caused by play in the first controlled object 560, and at least a portion of the torque ripple occurring in the first controlled object 560.

[0130] The first corrected torque T used for model following control in the first model following control unit 230 f1 In order to apply friction compensation and disturbance compensation performed in the assist adjustment unit 270, it is necessary to pay attention to the stability conditions of the model following control. This condition, according to the small gain theorem described later, is that the gain in the gain characteristics of the transfer function of the assist adjustment unit 270, constrained to characteristics that take stability into consideration, does not exceed 1. This is derived from the design conditions of the second filter 232b. In this embodiment, the values ​​of gains K3 and K4 in the gain adjusters 253 and 263 are set to a maximum of 1, and subtraction processing is applied by providing a subtractor SU4 before the limiters 252 and 262 so that the gain in the gain characteristics under these conditions becomes 1. In other words, the assist adjustment unit 270 behaves as a low-pass filter having a transfer function of 1-Q1(s). Q1(s) is the transfer function of the first filter 232a, which is a high-pass filter. The assist adjustment unit 270 applies a low-pass filter process with a transfer function of 1-Q1(s) to the torque output from the second filter 232b, and the friction compensation value calculation unit 250 and the disturbance compensation value calculation unit 260 adjust and output the processed value, respectively.

[0131] Furthermore, the values ​​of the gains K3 and K4 described above are determined so that the friction force component is compensated 100% in both manual and automatic driving modes. Here, the friction compensation value calculation unit 250 compensates only the friction force component, while the disturbance compensation value calculation unit 260 compensates all disturbances, including the friction force component. In automatic driving mode, for example, it is preferable to compensate for almost all disturbances, so the gain K4 of the disturbance compensation value calculation unit 260 is approximately 1. In this case, since the friction force component is also almost entirely compensated by the compensation by the disturbance compensation value calculation unit 260, the gain K3 of the friction compensation value calculation unit 250 is zero. On the other hand, in passive driving mode, the self-aligning torque T SAT It is preferable to leave some of the tire reaction force, including the above, to make it easier for the driver to operate the vehicle V, while compensating 100% of the friction force component. For this reason, in manual driving mode, it is preferable to set the gain K4 of the disturbance compensation value calculation unit 260 to less than 1, and to compensate the friction force component not compensated by the disturbance compensation value calculation unit 260 with the friction compensation value calculation unit 250. For example, if the gain K4 of the disturbance compensation value calculation unit 260 is 0.8 in manual driving mode, the gain K3 of the friction compensation value calculation unit 250 is set to 0.2, and the 20% friction force component not compensated by the disturbance compensation value calculation unit 260 is compensated by the friction compensation value calculation unit 250.

[0132] The adder AD4 adds the output value from the assist adjustment unit 270 to the output value from the first filter 232a. In other words, the adder AD4 adds the frequency component T aM Friction compensation value V f and disturbance compensation value V d Add and . Adder AD4 outputs the frequency component T aM and friction compensation value V f and disturbance compensation value V d The first corrected torque T is calculated by adding these together. f1 The following is output. The first corrected torque T is output from adder AD4. f1 This is the input to the first controlled object 560, i.e., the command torque T rL1This is fed back to the first model following control unit 230. a , that is, frequency component T aM For this, the friction compensation value V f and disturbance compensation value V d Adding these together gives the first corrected torque T f1 Generates.

[0133] The first state feedback unit 280 determines the apparent transfer function of the first controlled object 560 based on the output of the first controlled object 560, and the transfer function P of the first nominal model NM1. sn (s) should be approached, state compensation value V s Command torque T rL1 Feedback is provided to the first controlled object 560. The apparent transfer function of the first controlled object 560 is, for example, the transfer function of a single part when the part located inside the feedback loop created by the first model following control unit 230 is considered as a single part. Specifically, in this embodiment, the apparent transfer function of the first controlled object 560 is the transfer function of the entire part from the subtractor SU2 to the output of the first controlled object 560, and is the transfer function of the part that combines the first state feedback unit 280 and the first controlled object 560. In this embodiment, the first state feedback unit 280 is the first corrected torque T f1 The command torque T after correction and before input to the first controlled object 560 rL1 For this, the state compensation value V s Provide feedback.

[0134] State compensation value V s This includes a compensation value that compensates for at least a portion of the inertial force, viscous force, and frictional force acting on the first controlled object 560. More specifically, the state compensation value V s This includes a compensation value that compensates for at least a portion of the inertial force, viscous force, and frictional force generated in the motor 543. In this embodiment, the state compensation value Vs This is a compensation value that includes the inertial force, viscous force, and frictional force acting on the motor 543, respectively.

[0135] The first state feedback unit 280 includes an inertia compensator 281, a viscosity compensator 282, and a friction compensator 283. The inertia compensator 281 controls the steering angle θ. s Based on this, a compensation value is calculated to compensate for at least a portion of the inertial force generated in the motor 543. The viscous compensator 282 controls the steering angle θ s Based on this, a compensation value is calculated to compensate for at least a portion of the viscous force generated in the motor 543. The friction compensator 283 controls the steering angle θ. s Based on this, a compensation value is calculated that compensates for at least a portion of the frictional force generated in the motor 543. In this embodiment, the state compensation value V s This consists of a compensation value calculated by the inertia compensator 281, a compensation value calculated by the viscosity compensator 282, and a compensation value calculated by the friction compensator 283. The compensation value calculated by the inertia compensator 281, the compensation value calculated by the viscosity compensator 282, and the compensation value calculated by the friction compensator 283 are output to the adder AD3 to form the first corrected torque T f1 Command torque T after correction rL1 It will be added to.

[0136] The calculation unit 292 inputs a third input value θ to the first model-following control unit 230 based on the output from the first controlled object 560. i The output from the first controlled object 560 is the rotation angle θ of the motor 543, which is obtained based on the angle sensor 112. m The steering angle θ obtained based on the steering torque sensor 541 and the steering angle sensor 542. s The calculation unit 292 includes the rotation angle θ. m And, steering angle θ s The input is θ. As shown in Figure 15, the calculation unit 292 has a high-pass filter unit 292H and a low-pass filter unit 292L. The rotation angle θ input to the calculation unit 292 mThe signal is then divided by the reduction ratio N of the reduction mechanism 544, and then subjected to high-pass filtering in the high-pass filter section 292H to obtain a high-frequency output value θ. mf The reduction ratio N is the value obtained by dividing the rotational angular velocity of motor 543 by the rotational angular velocity of the output of reduction mechanism 544. The reduction ratio N and the rotational angle θ of motor 543 m and steering angle θ s That is, N=θ m / θ s The relationship is satisfied. High-frequency output value θ mf This is the first output value, which is the rotation angle θ. m This value is obtained by applying a high-pass filter and a division process by dividing it by the reduction ratio N of the reduction mechanism 544. The steering angle θ input to the calculation unit 292 s The low-pass filter section 292L performs low-pass filtering to obtain a low-frequency output value θ. sf This is the result. Low-frequency output value θ sf This is the steering angle θ, which is the second output value. s This value is obtained by applying a low-pass filter to the given signal. In this embodiment, the low-pass filter performed in the low-pass filter unit 292L corresponds to the "second low-pass filter."

[0137] In this embodiment, the cutoff frequency of the high-pass filter section 292H and the cutoff frequency of the low-pass filter section 292L are the same. That is, in this embodiment, the cutoff frequency in the high-pass filtering process performed in the calculation unit 292 is the same as the cutoff frequency in the low-pass filtering process performed in the calculation unit 292. In the following description, the cutoff frequency of the high-pass filter section 292H and the cutoff frequency of the low-pass filter section 292L are referred to as the cutoff frequency Cf3. The cutoff frequency Cf3 is lower than the first cutoff frequency Cf1. The cutoff frequency Cf3 is between 0.05Hz and 50Hz. In this embodiment, the cutoff frequency Cf3 is between 0.05Hz and 30Hz. More specifically, the cutoff frequency Cf3 is 5Hz or less.

[0138] Furthermore, "the cutoff frequency in high-pass filtering is the same as the cutoff frequency in low-pass filtering" includes not only cases where the cutoff frequencies in high-pass filtering and low-pass filtering are exactly the same, but also cases where they are approximately the same. "The cutoff frequency in high-pass filtering and low-pass filtering are approximately the same" includes cases where the cutoff frequencies in high-pass filtering and low-pass filtering differ from each other within the tolerance range of manufacturing variations of the filters performing each filtering process.

[0139] High-frequency output value θ mf The gain and low-frequency output value θ sf The gain has a frequency characteristic as shown in the graph in Figure 16. In the graph in Figure 16, the horizontal axis represents the frequency f [Hz], and the vertical axis represents the gain of each output value. As shown in Figure 16, the frequency band below the cutoff frequency Cf3 is the first frequency band FB1. The frequency band above the cutoff frequency Cf3 is the second frequency band FB2.

[0140] High-frequency output value θ in the first frequency band FB1 mf The gain is the high-frequency output value θ in the second frequency band FB2. mf It is smaller than the gain. High-frequency output value θ at cutoff frequency Cf3 mf The gain is less than 1. The high-frequency output value θ at the cutoff frequency Cf3. mf The gain is, for example, 1 / √2, or -3 [dB]. The high-frequency output value θ mf The gain is 1 in the frequency band above the cutoff frequency Cf3, specifically above the frequency fb. The high-frequency output value θ is below the frequency fb. mf The gain decreases as the frequency f decreases.

[0141] Low-frequency output value θ in the second frequency band FB2 sf The gain is the low-frequency output value θ in the first frequency band FB1.sf It is smaller than the gain. Low-frequency output value θ at cutoff frequency Cf3 sf The gain is less than 1. In the example in Figure 16, the low-frequency output value θ at the cutoff frequency Cf3. sf The gain is the high-frequency output value θ at the cutoff frequency Cf3. mf This is the same as the gain. The low-frequency output value θ at the cutoff frequency Cf3. sf The gain is, for example, 1 / √2, or -3 [dB]. Low frequency output value θ sf The gain is 1 in the frequency band below the cutoff frequency Cf3, specifically below the frequency fa. In the frequency band above the frequency fa, the low-frequency output value θ is... sf The gain of the signal decreases as the frequency f increases.

[0142] As shown in Figure 15, in the calculation unit 292, the high-frequency output value θ mf and low-frequency output value θ sf These are added together by the adder AD8. The adder AD8 has a high-frequency output value θ mf and low-frequency output value θ sf Adding these together, the sum of these values ​​becomes the third input value θ i It outputs as follows. In this way, the calculation unit 292 calculates the rotation angle θ m The high-frequency output value θ is obtained by applying a high-pass filter and a division process by the reduction ratio N to the given value. mf And, steering angle θ s The low-frequency output value θ obtained by applying a low-pass filter to it. sf The third input value θ is obtained by adding these together. i The following is calculated. In other words, the control method for controlling the first controlled object 560 is the high-frequency output value θ. mf And the low-frequency output value θ sf The third input value θ is obtained by adding these together. i This includes calculating [the value].

[0143] Next, the control by the first model following control unit 230 will be described in more detail. The first model following control unit 230 controls the first control target 560 using the inverse model of the first nominal model NM1, which it has as an internal model, i.e., the first inverse nominal model 231. In this embodiment, the feedback loop created by the first model following control unit 230 makes it possible to compensate for torque ripple and other factors that depend on the angular velocity of the motor 543.

[0144] The first model following control unit 230 is structurally similar to a conventional disturbance estimator (disturbance observer), but its intended function and effect are different. Conventional disturbance estimators estimate disturbance torque by using an inverse plant model, which is an internal model, that is close to the first controlled object 560, and reduce the effect of disturbances by adding or subtracting the disturbance torque in advance.

[0145] The control by the first model following control unit 230 in this embodiment uses a feedback loop to control the transfer function P of the first controlled object 560. s (s) has a transfer function P of the first nominal model NM1 as an internal model. sn The effect of being constrained by (s) is utilized. For example, if the first nominal model NM1 is defined so that there is no torque ripple, the transfer function P of the first controlled object 560 can be determined by model following control. s(s) is constrained to characteristics without torque ripple, and as a result, torque ripple can be reduced by applying torque ripple compensation. Furthermore, by making the first nominal model NM1 a low-inertia model and constraining the first controlled object 560 with the first nominal model NM1, the first controlled object 560 can be treated as a low-inertia model. Furthermore, by making the first nominal model NM1 a low-viscosity model and constraining the first controlled object 560 with the first nominal model NM1, the first controlled object 560 can also be treated as a low-viscosity model. By executing model following control by the first model following control unit 230, in addition to torque ripple compensation for the motor 543, for example, lost torque compensation or motor inertia compensation is performed. In the above-mentioned equations (17) and (18), J n and B n By setting it appropriately, the transfer function P of the first controlled object 560 can be determined. s The desired frequency characteristics can be imparted to (s).

[0146] Transfer function P of the first controlled object 560 s (s) and the transfer function P of the first nominal model NM1 sn When the modeling error with (s) is denoted as Δ(s), the transfer function P of the first controlled object 560 is s (s) can be expressed, for example, by the following equation (19).

[0147]

number

[0148] Furthermore, the transfer function P of the first controlled object 560 s (s), that is, the plant characteristics in the model following control of the first model following control unit 230, are not limited to the example of equation (19) above and may be expressed in any way. Transfer function P of the first controlled object 560 s (s) may be expressed as two inertial frames of reference, or as an equation derived by a higher-order approximation.

[0149] Transfer function P of the first controlled object 560s The gain characteristic of (s) has peaks at two frequency values, for example. The modeling error Δ(s) appears, for example, near the higher frequency peak of the two peaks in the gain characteristic of the first controlled object 560. Therefore, as shown in Figure 13, the reciprocal of the modeling error Δ(s), 1 / Δ(s), has a bottom in the relatively high frequency region. In Figure 13, the modeling error Δ(s) is shown as an absolute value. As the modeling error Δ(s) increases, the transfer function P of the first controlled object 560 s (s) and the transfer function P of the first nominal model NM1 sn The deviation from (s) becomes large, and the control of the first controlled object 560 using the first nominal model NM1 by the first model following control unit 230 becomes unstable. Therefore, in the region where the modeling error Δ(s) is relatively small, the gain of the complementary sensitivity function T(s) is set to approximately 1, and the first controlled object 560 is constrained to the first nominal model NM1, thereby enabling stable and suitable control of the first controlled object 560. Transfer function P of the first nominal model NM1 sn (s) J n and B n By adjusting the modeling error Δ(s), the frequency characteristics of the modeling error Δ(s) are adjusted. By adjusting the first cutoff frequency Cf1 and the second cutoff frequency Cf2, the frequency band in which the gain of the complementary sensitivity function T(s) is approximately 1 is adjusted. This allows the gain of the complementary sensitivity function T(s) to be approximately 1 in the frequency band in which the modeling error Δ(s) is small.

[0150] In Figure 13, 1 / Δ(s) is relatively high in the frequency band below the second cutoff frequency Cf2, and decreases sharply in the frequency band above the second cutoff frequency Cf2. Model following control, which constrains the first controlled object 560 to the first nominal model NM1, can be performed stably, for example, in the range where 1 / Δ(s) is greater than 1, i.e., greater than 0 dB. Therefore, as shown in Figure 13, by adjusting 1 / Δ(s) to be greater than 1 in the frequency band where the gain of the complementary sensitivity function T(s) is approximately 1, the first controlled object 560 can be constrained to the first nominal model NM1 and controlled stably and suitably when the gain of the complementary sensitivity function T(s) is approximately 1.

[0151] For example, in order to broaden the frequency band over which the first controlled object 560 can be stably and suitably controlled by constraining it to the first nominal model NM1, the second cutoff frequency Cf2 should be increased within the range where 1 / Δ(s) is not less than 1, that is, within the frequency band lower than the frequency at which the curve representing 1 / Δ(s) in Figure 13 intersects with the horizontal axis. However, if the second cutoff frequency Cf2 is increased too much, the gain of the complementary sensitivity function T(s) may remain relatively high in the frequency band higher than the second cutoff frequency Cf2, even though 1 / Δ(s) has decreased, which may lead to unstable control. In contrast, in this embodiment, since the order of the second filter 232b, which is a low-pass filter, is set to the third order or higher, the gain of the complementary sensitivity function T(s) can be sharply reduced in the region where the frequency is higher than the second cutoff frequency Cf2. As a result, even if the second cutoff frequency Cf2 is set relatively high, the gain of the complementary sensitivity function T(s) can be quickly reduced in frequency bands higher than the second cutoff frequency Cf2, thereby suppressing instability in the control of the first controlled object 560.

[0152] The robust stability of the first model-following control unit 230 is guaranteed when the small gain theorem shown in equation (20) below holds between the complementary sensitivity function T(s) and the modeling error Δ(s).

[0153]

number

[0154] As described above, in order to perform model following control using the first nominal model NM1 in the first model following control unit 230, the complementary sensitivity gain GT of the complementary sensitivity function T(s) only needs to be approximately 1. However, considering robust stability, it is necessary to satisfy equation (20) above. As can be understood from this, it is not possible to reconcile making the complementary sensitivity gain GT approximately 1 in all frequency bands with equation (20), and therefore, the suppression of disturbances by the first model following control unit 230 and robust stability are incompatible.

[0155] As shown in Figure 13, even in the low-frequency region FA1, where the frequency f is lower than the first cutoff frequency Cf1, the complementary sensitivity gain GT of the complementary sensitivity function T(s) becomes less than 1. In the region where the complementary sensitivity gain GT of the complementary sensitivity function T(s) becomes less than 1, the command torque T rL1 The first controlled object 560 is controlled by performing this control. As described above, in the high-frequency region FA2, where the frequency is higher than the second cutoff frequency Cf2, the complementary sensitivity gain GT of the complementary sensitivity function T(s) is greatly reduced, and the first corrected torque T from the first model following control unit 230 is controlled. f1 This results in a state where there is almost no feedback to the input of the first controlled object 560. On the other hand, in the low-frequency region FA1, the complementary sensitivity gain GT of the complementary sensitivity function T(s) is set to a certain magnitude, and the first corrected torque T f1 This is fed back to the input of the first controlled object 560. In the low-frequency region FA1, the compensation value generated in the assist adjustment unit 270 described above is fed back to the input of the first controlled object 560 according to the complementary sensitivity gain GT of the complementary sensitivity function T(s). The value of the complementary sensitivity gain GT in the low-frequency region FA1 is, for example, 0.8 or more.

[0156] For example, if the communication period of the signal sent from the steering angle sensor 542 to the control device 100 is long, in the model following control performed by the first model following control unit 230 of the control device 100, the steering angle θ acquired based on the steering angle sensor 542 is in a frequency band higher than the frequency which is the reciprocal of the communication period. s In some cases, it may not be possible or may be difficult to use. In this case, the rotation angle θ of the motor 543 is used in a frequency band higher than the frequency which is the reciprocal of the communication cycle. m The value obtained by dividing this by the reduction ratio N of the reduction mechanism 544 is the steering angle θ obtained based on the steering angle sensor 542. s Instead, it can be used to perform model following control in the first model following control unit 230. However, in this case, the disturbance from the motor 543 to the output shaft 524b cannot be estimated in the model following control, and therefore cannot be compensated for. Specifically, in this case, the response delay element C of the output of the reduction mechanism 544 to the output of the motor 543 described above L (s) cannot be estimated and compensated for. Lane keeping control performed by the first assist control unit 210 does not allow steering angle θ s Control the steering angle θ h Because this control system controls the external disturbance, the inability to estimate the disturbance led to a problem where the responsiveness of the lane keeping control system deteriorated.

[0157] In response to the above problems, according to this embodiment, the control device 100 is capable of performing lane keeping control to maintain the vehicle V within the lane L, and the first command torque T LKA The first assist control unit 210 generates the steering torque T input from the steering wheel 521. h Based on the second command torque T r The second assist control unit 220 generates the first command torque T LKA and the second command torque T r Command torque T calculated based on rL1 The system includes a disturbance sensitivity control unit 290 to which the command torque T is input. rL1 The first corrective torque T corrects for the above. f1The system includes a first model following control unit 230 that generates a first nominal model NM1 based on the configuration of the first controlled object 560. The first model following control unit 230 is the inverse model of the first nominal model NM1 and represents the rotation angle θ of the motor 543. m The third input value θ based on i The first inverse nominal model 231 is input to the first control target 560, and the complementary sensitivity gain GT, which is the gain in the gain characteristic of the complementary sensitivity function T(s) with respect to the modeling error Δ(s) between the first control target 560 and the first nominal model NM1, is approximately 1 in the frequency band, and the transfer function P of the first control target 560 s (s) is the transfer function P of the first nominal model NM1. sn -1 The first assist control unit 210 is configured to be constrained to (s). The first assist control unit 210 is configured to be constrained to the target steering angle θ, which is the target value of the output of the reduction mechanism 544. sr Based on the first command torque T LKA It has a first generation unit 213 that generates a steering angle θ which indicates the output of the reduction mechanism 544. s This is fed back. The first generation unit 213 receives the feedback steering angle θ. s The system has a compensation unit 214 that performs phase delay compensation processing for the phase delay that occurs. In other words, the control method for controlling the first controlled object 560 is a first command torque T LKA The system generates a steering torque T and performs lane keeping control to maintain the vehicle V within lane L, and steering torque T h Based on the second command torque T r The process involves generating a model following control and executing model following control by the first model following control unit 230, and then, by the model following control, determining the transfer function P of the first controlled object 560 in a frequency band where the complementary sensitivity gain GT is approximately 1. s (s) is the transfer function P of the first nominal model NM1 sn -1 (s) includes being constrained to the model following control by the first model following control unit 230, the first inverse nominal model 231 receives a third input value θ i The input is as follows: Lane keeping control uses the target steering angle θ.sr Based on the first command torque T LKA To generate the steering angle θ s The feedback is given, and the steering angle θ is fed back. s This includes performing phase delay compensation processing for the phase delay that occurs.

[0158] Therefore, the steering angle θ is fed back to the first generation unit 213 of the first assist control unit 210. s The rotation angle θ that occurs m The delay in this regard can be compensated by the phase delay compensation processing performed by the compensation unit 214. This allows the rotation angle θ of the motor 543 to be compensated. m The third input value θ is based on i Even when model following control is performed by the first model following control unit 230 using the above-mentioned response delay element C, a decrease in the responsiveness of lane keeping control in the first assist control unit 210 can be suppressed. L By modeling (s) and designing the phase delay compensation processing performed by the compensation unit 214 based on this model, the decrease in the responsiveness of the lane keeping control can be more effectively suppressed.

[0159] According to this embodiment, the compensation unit 214 feeds back the steering angle θ to the first generation unit 213. s It has a phase delay element 216 that delays the phase. In other words, the phase delay compensation process is fed back the steering angle θ in lane keeping control. s This includes a process to delay the phase. As explained using equation (8), etc., the target steering angle θ sr The steering angle θ is subtracted from s Applying a phase delay process to it results in a phase advance effect. Therefore, by providing a phase delay element 216 in the compensation unit 214, the steering angle θ that is fed back to the first generation unit 213 is increased. s The rotation angle θ that occurs m This can compensate for the delay.

[0160] According to this embodiment, the control device 100 controls the rotation angle θ m The high-frequency output value θ is obtained by applying a high-pass filter and a division process by dividing it by the reduction ratio N of the reduction mechanism 544. mf And, steering angle θ s The low-frequency output value θ obtained by applying a low-pass filter to it. sf The third input value θ is obtained by adding these together. i The system includes a calculation unit 292 that calculates the high-frequency output value θ. In other words, the control method for controlling the first control target 560 is a control method for controlling the high-frequency output value θ. mf And the low-frequency output value θ sf The third input value θ is obtained by adding these together. i This includes calculating the third input value θ in the frequency band higher than 30Hz. The cutoff frequency Cf3 in the low-pass filter processing is 30Hz or less. i The frequency components are the rotation angle θ. m This value is obtained based on the following. Thus, over a wide frequency band, the rotation angle θ m The third input value θ obtained based on this is... i Even when model following control is performed using this method, according to this embodiment, as described above, a decrease in the responsiveness of lane keeping control can be suppressed. Furthermore, for example, even if the communication period of the signal sent from the steering angle sensor 542 using CAN is about 10 ms (microseconds), if the cutoff frequency Cf3 is 30 Hz or less, the model following control by the first model following control unit 230 can be suitably executed.

[0161] In this embodiment, the phase delay element 216 may be a low-pass filter. In other words, the phase delay process in the phase delay compensation process is the steering angle θ that is fed back in lane keeping control. s This may also be a first low-pass filter processing performed on the lane. Even in this case, as described above, it is possible to suppress a decrease in responsiveness in lane keeping control. In addition, in this case, the configuration of the phase delay element 216 can be simplified. When the phase delay element 216 is a low-pass filter, the transfer function C of the phase delay element 216 fp(s) can be expressed, for example, by replacing the numerator of equation (5) above with 1.

[0162] <Second Embodiment> As shown in Figure 17, the control device 100A of the lane keeping system 1100A in this embodiment differs from the first embodiment in the configuration of the controller 201A of the processor 200A. In this embodiment, the steering torque T output from the torque conversion unit 223 h This is input to the second assist control unit 220A. The second assist control unit 220A outputs the steering torque T from the torque conversion unit 223 based on the input value. h Except for the point that the second assist control unit 220 of the first embodiment is the same as the second assist control unit 220A. The second command torque T output from the second assist control unit 220A r This is input to the second gain adjustment unit 620A. The second gain adjustment unit 620A receives the input value and outputs the second command torque T from the second assist control unit 220A. r Except for the point that, it is the same as the second gain adjustment unit 620 of the first embodiment. The second gain adjustment unit 620A controls the second command torque T r Multiplying this by the second gain K2 gives the second command torque T r1 The second command torque T r1 This is output to the vehicle stabilization control unit 240A.

[0163] In this embodiment, the first command torque T output from the first gain adjustment unit 610 LKA1 This is input only to the vehicle stabilization control unit 240A. The vehicle stabilization control unit 240A receives the first command torque T LKA1 and the second command torque T r1 A command torque, which is the sum of these two values, is input. The other configurations of the vehicle stabilization control unit 240A are the same as the other configurations of the vehicle stabilization control unit 240 in the first embodiment.

[0164] In this embodiment, the vehicle stabilization control unit 240A receives a first command torque T, which is the first input value. LKA1 And the second input value is the second command torque T r1These are inputs independently of each other. Therefore, the output from the first assist control unit 210, adjusted by the first gain K1, and the output from the second assist control unit 220A, adjusted by the second gain K2, can be input to the vehicle stabilization control unit 240A regardless of the output of the other. This makes it easier to adjust the control amounts of each assist control unit.

[0165] In this specification, "the first input value and the second input value are input to the vehicle stabilization control unit independently of each other" means, for example, that the first input value and the second input value input to the vehicle stabilization control unit are calculated independently of the other input value.

[0166] The other configurations of the control device 100A are the same as those of the control device 100 in the first embodiment. The other configurations of the lane keeping system 1100A are the same as those of the lane keeping system 1100 in the first embodiment.

[0167] In this embodiment, the first input value output from the first assist control unit 210 may be an angle. In this case, the first input value may be input to the vehicle stabilization control unit 240A as an angle, or it may be converted to torque before being input to the vehicle stabilization control unit 240A. If the first input value is input to the vehicle stabilization control unit 240A as an angle, the second input value output from the second assist control unit 220A and input to the vehicle stabilization control unit 240A is also an angle.

[0168] <Third Embodiment> As shown in Figure 18, in the first assist control unit 210B of the control device 100B of this embodiment, the first generation unit 213B includes a torque calculation unit 215B and a subtractor SU8. In this embodiment, the first generation unit 213B generates a first command torque T by, for example, PD (Proportional-Differential) control. LKA The subtractor SU8 generates the target steering angle θ. sr From steering angle θ sThe result is subtracted and output to the torque calculation unit 215B. The torque calculation unit 215B includes a compensation unit 214B, a proportional gainer 217B, a differential gainer 218B, and an adder AD9.

[0169] The target steering angle θ input from the subtractor SU8 to the torque calculation unit 215B sr This is input to the proportional gainer 217B and the compensation unit 214B. The proportional gainer 217B receives the input target steering angle θ. sr proportional gain K P The result is multiplied and output to adder AD9. Compensation unit 214B includes differentiator 219B and phase lead element 216B. The target steering angle θ input to compensation unit 214B sr This is input to the differentiator 219B. The target steering angle θ input to the differentiator 219B sr This is differentiated and input to the phase lead element 216B. The phase lead element 216B controls the target steering angle θ sr From steering angle θ s This is a phase-leading element that advances the phase of the value obtained by subtracting from it. Transfer function C of phase-leading element 216B fd (s) can be expressed, for example, by the following equation (21).

[0170]

number

[0171] The value output from the phase-leading element 216B is the differential gain K in the differential gain unit 218B. D After being multiplied, the signal is input to adder AD9. Adder AD9 adds the output from proportional gainer 217B and the output from differential gainer 218B to produce the first command torque T LKA Generates.

[0172] The other configurations of the first assist control unit 210B are the same as the other configurations of the first assist control unit 210 in the first embodiment. The other configurations of the control device 100B are the same as the other configurations of the control device 100 in the first embodiment.

[0173] According to this embodiment, the compensation unit 214B controls the target steering angle θ. sr From steering angle θ s It has a phase-advancing element 216B that advances the phase of the value obtained by subtracting from it. In other words, the phase lag compensation process is performed on the target steering angle θ sr From steering angle θ s This process includes advancing the phase of the value obtained by subtracting from it. Therefore, the steering angle θ is fed back to the first generation unit 213B by the compensation unit 214B. s The rotation angle θ that occurs m This can compensate for the delay. Therefore, it can suppress a decrease in the responsiveness of lane keeping control.

[0174] Furthermore, in this embodiment, a phase-advancing element 216B is provided in the portion of the torque calculation unit 215B where differential control (D (Differential) control) is performed. Therefore, the effect of further advancing the phase can be obtained by the differentiator 219B. As a result, the steering angle θ is achieved by the phase-advancing element 216B and the differentiator 219B. s The rotation angle θ that occurs m This allows for more favorable compensation of the delay. Therefore, the decrease in the responsiveness of the lane keeping control can be more effectively suppressed.

[0175] At least some of the functions of each component of the control device in each of the embodiments described above may be implemented by hardware including circuit sections such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), and GPU (Graphics Processing Unit), or by the cooperation of software and hardware. The storage unit that stores the program causing the processor of the control device, which is a computer, to execute the control method described above is implemented by a storage medium such as RAM (Random Access Memory), ROM (Read Only Memory), HDD (hard disk drive), and flash memory. The storage unit is not particularly limited as long as it can store the program causing the computer to execute the control method described above, and may be a microcomputer or a disk medium such as a CD-ROM. The storage unit may be provided separately from the control device. In this case, the control device may communicate with the storage unit by wired communication or wireless communication and execute the program stored in the storage unit.

[0176] The present invention is not limited to the embodiments described above, and other configurations and methods can be adopted within the scope of the technical idea of ​​the present invention. The phase delay compensation processing performed in the compensation unit is performed by feeding back the second output value (steering angle θ). s Any processing method is acceptable as long as it can compensate for the phase delay that occurs in the ) process. The cutoff frequency in the high-pass filter processing performed in the arithmetic unit may be different from the cutoff frequency in the low-pass filter processing performed in the arithmetic unit. The cutoff frequencies in the high-pass filter processing and the low-pass filter processing performed in the arithmetic unit are not particularly limited.

[0177] Furthermore, this technology can be configured as follows: [1] A control device for controlling a portion of an electric power steering system mounted on a vehicle, which includes an input shaft to which a steering wheel operated by the driver is connected, an output shaft connected to the input shaft via a torsion bar, and a motor connected to the output shaft via a reduction mechanism, the control device being capable of performing lane keeping control to keep the vehicle within a lane, and comprising: a first assist control unit that generates a first input value; a second assist control unit that generates a second input value based on a steering input value input from the steering wheel; and a disturbance sensitivity control unit to which a command value calculated based on the first input value and the second input value is input, wherein the disturbance sensitivity control unit generates a correction value for correcting the command value based on a nominal model based on the configuration of the control device, and is a model follower A control device having an ing control unit, wherein the model-following control unit has an inverse nominal model which is the inverse model of the nominal model and receives a third input value based on a first output value indicating the output of the motor, and is configured such that the transfer function of the controlled object is constrained to the transfer function of the nominal model in a frequency band where the complementary sensitivity gain, which is the gain in the gain characteristic of the complementary sensitivity function for the modeling error between the controlled object and the nominal model, is approximately 1, and the first assist control unit has a generation unit which generates the first input value based on a target value of the output of the reduction mechanism, the generation unit receives a second output value indicating the output of the reduction mechanism as feedback, and the generation unit has a compensation unit which performs a phase delay compensation process for the phase delay occurring in the second output value that is fed back. [2] The control device according to [1], wherein the compensation unit has a phase delay element that delays the phase of the second output value that is fed back to the generation unit. [3] The control device according to [2], wherein the phase delay element is a low-pass filter. [4] The control device according to [1], wherein the compensation unit has a phase-advancing element that advances the phase of the value obtained by subtracting the second output value from the target value. [5] The control device according to any one of [1] to [4], comprising a calculation unit that calculates the third input value by adding a value obtained by applying a high-pass filter and a division process by dividing the first output value by the reduction ratio of the reduction mechanism and a value obtained by applying a low-pass filter to the second output value, wherein the cutoff frequency in the low-pass filter is 30 Hz or less. A motor device comprising a control device described in any one of items [1] to [5] [6] and the motor. An electric power steering system comprising the motor device described in [7] [6] and a steering mechanism having the input shaft, the output shaft, and the torsion bar. [8] A control method for controlling a portion of an electric power steering system mounted on a vehicle, which includes an input shaft to which a steering wheel operated by an operator is connected, an output shaft connected to the input shaft via a torsion bar, and a motor connected to the output shaft via a reduction mechanism, the control method comprising: generating a first input value and performing lane keeping control to maintain the vehicle within the lane; generating a second input value based on a steering input value input from the steering wheel; and performing model following control to generate a correction value for correcting a command value calculated based on the first input value and the second input value, based on a nominal model based on the configuration of the control target; and using the model following control The control method includes constraining the transfer function of the controlled object to the transfer function of the nominal model in a frequency band where the complementary sensitivity gain, which is the gain in the gain characteristic of the complementary sensitivity function for the modeling error between the controlled object and the nominal model, is approximately 1, wherein in the model-following control, a third input value based on a first output value indicating the output of the motor is input to an inverse nominal model which is the inverse model of the nominal model, and the lane-keeping control method includes generating the first input value based on a target value of the output of the deceleration mechanism, feeding back a second output value indicating the output of the deceleration mechanism, and performing phase delay compensation processing for the phase delay occurring in the second output value that is fed back. [9] The control method according to [8], wherein the phase delay compensation process includes a process to delay the phase of the second output value that is fed back in the lane keeping control.

[10] The control method according to [9], wherein the phase delaying process is a first low-pass filter process performed on the second output value that is fed back in the lane keeping control.

[11] The control method according to [8], wherein the phase delay compensation process includes a process of advancing the phase of the value obtained by subtracting the second output value from the target value.

[12] The control method according to any one of [8] to

[11] , which includes calculating the third input value by adding a value obtained by applying a high-pass filter and a division process by dividing the first output value by the reduction ratio of the reduction mechanism and a value obtained by applying a second low-pass filter to the second output value, wherein the cutoff frequency in the second low-pass filter is 30 Hz or less.

[13] A program that causes a computer to execute one of the control methods described in any one of the items from [8] to

[12] .

[0178] The configurations and methods described herein can be combined as appropriate, within the bounds of non-inconsistency. [Explanation of Symbols]

[0179] 100, 100A, 100B... Control device, 100a... Motor device, 210, 210B... First assist control unit, 213, 213B... First generation unit (generation unit), 214, 214B... Compensation unit, 216... Phase lag element, 216B... Phase lead element, 220, 220A... Second assist control unit, 230... First model following control unit (model following control unit), 231... First inverse nominal model (inverse nominal model), 290... External Randomness sensitivity control unit, 292...Calculation unit, 521...Handle, 524a...Input shaft, 524b...Output shaft, 530...Steering mechanism, 543...Motor, 544...Reduction mechanism, 546...Torsion bar, 560...First controlled object (controlled object), 1000...Electric power steering device, Cf3...Cutoff frequency, GT...Complementary sensitivity gain, L...Lane, N...Reduction ratio, NM1...First nominal model (nominal model), T(s)...Complementary sensitivity function, T f1 ...First corrected torque (corrected value), T h ...Steering torque (steering input value), T LKA ...First command torque (first input value), T r ...Second command torque (second input value), T rL1 ...Command torque (command value), V...vehicle, θ i ...Third input value, θ m ...rotation angle (first output value), θ s ...Steering angle (second output value), θ sr ...Target steering angle (target value)

Claims

1. A control device for controlling the portion of an electric power steering system mounted on a vehicle, which includes an input shaft to which a steering wheel operated by the driver is connected, an output shaft connected to the input shaft via a torsion bar, and a motor connected to the output shaft via a reduction mechanism, the portion including the motor and the reduction mechanism being controlled, A first assist control unit capable of performing lane keeping control to keep the vehicle within the lane and generating a first input value, A second assist control unit generates a second input value based on the steering input value input from the steering wheel, A disturbance sensitivity control unit receives a command value calculated based on the first input value and the second input value, Equipped with, The disturbance sensitivity control unit includes a model following control unit that generates a correction value for correcting the command value based on a nominal model based on the configuration of the controlled object. The model-following control unit has an inverse nominal model which is the inverse model of the nominal model and receives a third input value based on a first output value indicating the output of the motor, and is configured such that the transfer function of the controlled object is constrained to the transfer function of the nominal model in a frequency band where the complementary sensitivity gain, which is the gain in the gain characteristic of the complementary sensitivity function for the modeling error between the controlled object and the nominal model, is approximately 1. The first assist control unit has a generation unit that generates the first input value based on the target value of the output of the deceleration mechanism, The generation unit receives a second output value indicating the output of the reduction mechanism as feedback. The control device includes a generation unit and a compensation unit that performs phase delay compensation processing for the phase delay that occurs in the second output value that is fed back.

2. The control device according to claim 1, wherein the compensation unit has a phase delay element that delays the phase of the second output value that is fed back to the generation unit.

3. The control device according to claim 2, wherein the phase delay element is a low-pass filter.

4. The control device according to claim 1, wherein the compensation unit has a phase-advancing element that advances the phase of the value obtained by subtracting the second output value from the target value.

5. The system includes a calculation unit that calculates the third input value by adding together a value obtained by applying a high-pass filter and a division process by dividing the first output value by the reduction ratio of the reduction mechanism, and a value obtained by applying a low-pass filter to the second output value. The control device according to claim 1, wherein the cutoff frequency in the low-pass filter processing is 30 Hz or less.

6. A control device according to any one of claims 1 to 5, The motor and, A motor device equipped with the following features.

7. The motor device according to claim 6, A steering mechanism having the input shaft, the output shaft, and the torsion bar, An electric power steering system equipped with this system.

8. A control method for controlling the portion of an electric power steering system mounted on a vehicle, which includes an input shaft to which a steering wheel operated by the driver is connected, an output shaft connected to the input shaft via a torsion bar, and a motor connected to the output shaft via a reduction mechanism, wherein the control target is the portion including the motor and the reduction mechanism. The first input value is generated and lane keeping control is performed to keep the vehicle within the lane, A second input value is generated based on the steering input value input from the aforementioned steering wheel, This involves performing model-following control to generate a correction value for correcting the command value calculated based on the first and second input values, based on a nominal model based on the configuration of the controlled object. The model-following control constrains the transfer function of the controlled object to the transfer function of the nominal model in a frequency band where the complementary sensitivity gain, which is the gain in the gain characteristic of the complementary sensitivity function with respect to the modeling error between the controlled object and the nominal model, is approximately 1. Includes, In the aforementioned model-following control, a third input value based on a first output value representing the motor output is input to an inverse nominal model, which is the inverse model of the nominal model. The lane keeping control described above is: The first input value is generated based on the target value of the output of the reduction mechanism, The second output value indicating the output of the reduction mechanism is fed back, The process involves performing phase delay compensation processing for the phase delay that occurs in the second output value that is fed back, A control method including

9. The control method according to claim 8, wherein the phase delay compensation process includes a process to delay the phase of the second output value that is fed back in the lane keeping control.

10. The control method according to claim 9, wherein the phase delaying process is a first low-pass filter process performed on the second output value that is fed back in the lane keeping control.

11. The control method according to claim 8, wherein the phase delay compensation process includes a process of advancing the phase of the value obtained by subtracting the second output value from the target value.

12. The process includes calculating the third input value by adding together the value obtained by applying a high-pass filter and a division process by dividing the first output value by the reduction ratio of the reduction mechanism, and the value obtained by applying a second low-pass filter to the second output value. The control method according to claim 8, wherein the cutoff frequency in the second low-pass filter processing is 30 Hz or less.

13. A program that causes a computer to execute the control method described in any one of claims 8 to 12.

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